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DOE OSTI2020

Materials Data on Mg2Si3 by Materials Project

Mg2Si3 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eight inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a 7-coordinate geometry to seven Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.77–2.86 Å. In the second Mg2+ site, Mg2+ is bonded to six Si+1.33- atoms to form distorted edge-sharing MgSi6 pentagonal pyramids. There are a spread of Mg–Si bond distances ranging from 2.71–3.07 Å. In the third Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.73–3.08 Å. In the fourth Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.73–3.03 Å. In the fifth Mg2+ site, Mg2+ is bonded in a 8-coordinate geometry to eight Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.75–3.05 Å. In the sixth Mg2+ site, Mg2+ is bonded in a 7-coordinate geometry to seven Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.73–2.90 Å. In the seventh Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.61–3.09 Å. In the eighth Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.75–3.05 Å. There are twelve inequivalent Si+1.33- sites. In the first Si+1.33- site, Si+1.33- is bonded in a 6-coordinate geometry to three Mg2+ and three Si+1.33- atoms. There are a spread of Si–Si bond distances ranging from 2.40–2.42 Å. In the second Si+1.33- site, Si+1.33- is bonded in a 6-coordinate geometry to three Mg2+ and three Si+1.33- atoms. Both Si–Si bond lengths are 2.43 Å. In the third Si+1.33- site, Si+1.33- is bonded in a 7-coordinate geometry to four Mg2+ and three Si+1.33- atoms. The Si–Si bond length is 2.42 Å. In the fourth Si+1.33- site, Si+1.33- is bonded in a 7-coordinate geometry to four Mg2+ and three Si+1.33- atoms. The Si–Si bond length is 2.41 Å. In the fifth Si+1.33- site, Si+1.33- is bonded in a 7-coordinate geometry to five Mg2+ and two Si+1.33- atoms. There are one shorter (2.35 Å) and one longer (2.42 Å) Si–Si bond lengths. In the sixth Si+1.33- site, Si+1.33- is bonded in a 8-coordinate geometry to six Mg2+ and two Si+1.33- atoms. There are one shorter (2.41 Å) and one longer (2.47 Å) Si–Si bond lengths. In the seventh Si+1.33- site, Si+1.33- is bonded in a 1-coordinate geometry to two Mg2+ and three Si+1.33- atoms. There are a spread of Si–Si bond distances ranging from 2.41–2.46 Å. In the eighth Si+1.33- site, Si+1.33- is bonded in a 6-coordinate geometry to three Mg2+ and three Si+1.33- atoms. Both Si–Si bond lengths are 2.40 Å. In the ninth Si+1.33- site, Si+1.33- is bonded in a 8-coordinate geometry to five Mg2+ and three Si+1.33- atoms. In the tenth Si+1.33- site, Si+1.33- is bonded in a 7-coordinate geometry to four Mg2+ and three Si+1.33- atoms. In the eleventh Si+1.33- site, Si+1.33- is bonded in a 8-coordinate geometry to six Mg2+ and two Si+1.33- atoms. In the twelfth Si+1.33- site, Si+1.33- is bonded in a 8-coordinate geometry to six Mg2+ and two Si+1.33- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Li12Si7 by Materials Project

Li12Si7 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are thirteen inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded in a distorted trigonal planar geometry to three Si+1.71- atoms. There are two shorter (2.64 Å) and one longer (2.95 Å) Li–Si bond lengths. In the second Li1+ site, Li1+ is bonded in a 5-coordinate geometry to five Si+1.71- atoms. There are a spread of Li–Si bond distances ranging from 2.63–2.88 Å. In the third Li1+ site, Li1+ is bonded in a 4-coordinate geometry to four Si+1.71- atoms. There are a spread of Li–Si bond distances ranging from 2.65–2.78 Å. In the fourth Li1+ site, Li1+ is bonded in a 4-coordinate geometry to four Si+1.71- atoms. There are a spread of Li–Si bond distances ranging from 2.62–2.97 Å. In the fifth Li1+ site, Li1+ is bonded in a 3-coordinate geometry to five Si+1.71- atoms. There are a spread of Li–Si bond distances ranging from 2.57–3.01 Å. In the sixth Li1+ site, Li1+ is bonded in a 5-coordinate geometry to five Si+1.71- atoms. There are a spread of Li–Si bond distances ranging from 2.59–2.80 Å. In the seventh Li1+ site, Li1+ is bonded in a 5-coordinate geometry to five Si+1.71- atoms. There are a spread of Li–Si bond distances ranging from 2.62–2.81 Å. In the eighth Li1+ site, Li1+ is bonded in a 5-coordinate geometry to five Si+1.71- atoms. There are a spread of Li–Si bond distances ranging from 2.68–2.82 Å. In the ninth Li1+ site, Li1+ is bonded in a 5-coordinate geometry to five Si+1.71- atoms. There are a spread of Li–Si bond distances ranging from 2.67–2.79 Å. In the tenth Li1+ site, Li1+ is bonded in a 10-coordinate geometry to ten Si+1.71- atoms. There are a spread of Li–Si bond distances ranging from 2.82–3.11 Å. In the eleventh Li1+ site, Li1+ is bonded in a trigonal non-coplanar geometry to three Si+1.71- atoms. There are a spread of Li–Si bond distances ranging from 2.64–2.87 Å. In the twelfth Li1+ site, Li1+ is bonded in a 6-coordinate geometry to one Li1+ and five Si+1.71- atoms. The Li–Li bond length is 2.40 Å. There are a spread of Li–Si bond distances ranging from 2.67–2.92 Å. In the thirteenth Li1+ site, Li1+ is bonded in a 6-coordinate geometry to five Si+1.71- atoms. There are a spread of Li–Si bond distances ranging from 2.68–2.83 Å. There are nine inequivalent Si+1.71- sites. In the first Si+1.71- site, Si+1.71- is bonded in a 10-coordinate geometry to eight Li1+ and two Si+1.71- atoms. There are one shorter (2.36 Å) and one longer (2.39 Å) Si–Si bond lengths. In the second Si+1.71- site, Si+1.71- is bonded in a 10-coordinate geometry to eight Li1+ and two Si+1.71- atoms. The Si–Si bond length is 2.37 Å. In the third Si+1.71- site, Si+1.71- is bonded in a 11-coordinate geometry to nine Li1+ and two Si+1.71- atoms. The Si–Si bond length is 2.37 Å. In the fourth Si+1.71- site, Si+1.71- is bonded in a 11-coordinate geometry to ten Li1+ and one Si+1.71- atom. The Si–Si bond length is 2.39 Å. In the fifth Si+1.71- site, Si+1.71- is bonded in a 10-coordinate geometry to nine Li1+ and one Si+1.71- atom. The Si–Si bond length is 2.39 Å. In the sixth Si+1.71- site, Si+1.71- is bonded in a 11-coordinate geometry to ten Li1+ and one Si+1.71- atom. The Si–Si bond length is 2.37 Å. In the seventh Si+1.71- site, Si+1.71- is bonded in a 10-coordinate geometry to seven Li1+ and three Si+1.71- atoms. In the eighth Si+1.71- site, Si+1.71- is bonded in a 10-coordinate geometry to eight Li1+ and two Si+1.71- atoms. The Si–Si bond length is 2.38 Å. In the ninth Si+1.71- site, Si+1.71- is bonded in a 10-coordinate geometry to nine Li1+ and two Si+1.71- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca8Al9Fe3Si12(HO13)4 by Materials Project

Ca8Fe3Al9Si12(HO13)4 crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are eight inequivalent Ca sites. In the first Ca site, Ca is bonded in a 1-coordinate geometry to eight O atoms. There are a spread of Ca–O bond distances ranging from 2.26–2.85 Å. In the second Ca site, Ca is bonded in a 1-coordinate geometry to ten O atoms. There are a spread of Ca–O bond distances ranging from 2.27–3.04 Å. In the third Ca site, Ca is bonded in a 1-coordinate geometry to ten O atoms. There are a spread of Ca–O bond distances ranging from 2.26–3.04 Å. In the fourth Ca site, Ca is bonded in a 1-coordinate geometry to ten O atoms. There are a spread of Ca–O bond distances ranging from 2.26–3.04 Å. In the fifth Ca site, Ca is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Ca–O bond distances ranging from 2.30–2.59 Å. In the sixth Ca site, Ca is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Ca–O bond distances ranging from 2.32–2.59 Å. In the seventh Ca site, Ca is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Ca–O bond distances ranging from 2.32–2.59 Å. In the eighth Ca site, Ca is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Ca–O bond distances ranging from 2.33–2.59 Å. There are three inequivalent Fe sites. In the first Fe site, Fe is bonded to six O atoms to form FeO6 octahedra that share corners with five SiO4 tetrahedra and edges with two equivalent AlO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.90–2.27 Å. In the second Fe site, Fe is bonded to six O atoms to form FeO6 octahedra that share corners with five SiO4 tetrahedra and edges with two equivalent AlO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.90–2.26 Å. In the third Fe site, Fe is bonded to six O atoms to form FeO6 octahedra that share corners with five SiO4 tetrahedra and edges with two equivalent AlO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.91–2.28 Å. There are five inequivalent Al sites. In the first Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with four SiO4 tetrahedra and edges with two equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–1.96 Å. In the second Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with four SiO4 tetrahedra and edges with two equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–1.95 Å. In the third Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with four SiO4 tetrahedra, an edgeedge with one FeO6 octahedra, and edges with three AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–1.99 Å. In the fourth Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with four SiO4 tetrahedra, edges with two FeO6 octahedra, and edges with two equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.86–1.99 Å. In the fifth Al site, Al is bonded to six O atoms to form distorted AlO6 octahedra that share corners with five SiO4 tetrahedra and edges with two equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.80–2.29 Å. There are twelve inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with six AlO6 octahedra. The corner-sharing octahedra tilt angles range from 47–54°. There are a spread of Si–O bond distances ranging from 1.65–1.68 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent FeO6 octahedra and corners with four AlO6 octahedra. The corner-sharing octahedra tilt angles range from 48–53°. There are a spread of Si–O bond distances ranging from 1.64–1.69 Å. In the third Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent FeO6 octahedra and corners with four AlO6 octahedra. The corner-sharing octahedra tilt angles range from 48–53°. There are a spread of Si–O bond distances ranging from 1.64–1.68 Å. In the fourth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent FeO6 octahedra and corners with four AlO6 octahedra. The corner-sharing octahedra tilt angles range from 48–53°. There are a spread of Si–O bond distances ranging from 1.64–1.69 Å. In the fifth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with four AlO6 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–57°. There are a spread of Si–O bond distances ranging from 1.59–1.67 Å. In the sixth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent FeO6 octahedra, corners with two equivalent AlO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–56°. There are a spread of Si–O bond distances ranging from 1.59–1.67 Å. In the seventh Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent FeO6 octahedra, corners with two equivalent AlO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–56°. There are a spread of Si–O bond distances ranging from 1.59–1.67 Å. In the eighth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent FeO6 octahedra, corners with two equivalent AlO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–56°. There are a spread of Si–O bond distances ranging from 1.59–1.67 Å. In the ninth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three AlO6 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 28–52°. There is one shorter (1.61 Å) and three longer (1.64 Å) Si–O bond length. In the tenth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one FeO6 octahedra, corners with two equivalent AlO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 35–54°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the eleventh Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one FeO6 octahedra, corners with two equivalent AlO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 36–54°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the twelfth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one FeO6 octahedra, corners with two equivalent AlO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 35–54°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. There are three inequivalent H sites. In the first H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.99 Å. In the second H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.98 Å. In the third H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.98 Å. There are forty inequivalent O sites. In the first O site, O is bonded in a trigonal non-coplanar geometry to three Al atoms. In the second O site, O is bonded in a trigonal non-coplanar geometry to one Fe and two equivalent Al atoms. In the third O site, O is bonded in a trigonal non-coplanar geometry to one Fe and two equivalent Al atoms. In the fourth O site, O is bonded in a trigonal non-coplanar geometry to one Fe and two equivalent Al atoms. In the fifth O site, O is bonded in a 2-coordinate geometry to two Ca, one Al, and one Si atom. In the sixth O site, O is bonded in a 4-coordinate geometry to two Ca, one Fe, and one Si atom. In the seventh O site, O is bonded in a 4-coordinate geometry to two Ca, one Fe, and one Si atom. In the eighth O site, O is bonded in a 4-coordinate geometry to two Ca, one Fe, and one Si atom. In the ninth O site, O is bonded in a 4-coordinate geometry to one Ca, two equivalent Al, and one Si atom. In the tenth O site, O is bonded in a 4-coordinate geometry to one Ca, two equivalent Al, and one Si atom. In the eleventh O site, O is bonded in a 4-coordinate geometry to one Ca, two equivalent Al, and one Si atom. In the twelfth O site, O is bonded in a 4-coordinate geometry to one Ca, two equivalent Al, and one Si atom. In the thirteenth O site, O is bonded in a distorted single-bond geometry to one Ca, two equivalent Al, and one H atom. In the fourteenth O site, O is bonded in a distorted single-bond geometry to one Ca, two equivalent Al, and one H atom. In the fifteenth O site, O is bonded in a distorted single-bond geometry to one Ca, two equivalent Al, and one H atom. The O–H bond length is 0.98 Å. In the sixteenth O site, O is bonded in a distorted single-bond geometry to one Ca, two equivalent Al, and one H atom. In the seventeenth O site, O is bonded in a bent 150 degrees geometry to one Al and one Si atom. In the eighteenth O site, O is bonded in a bent 150 degrees geometry to two equivalent Ca, one Fe, and one Si atom. In the nineteenth O site, O is bonded in a bent 150 degrees geometry to two equivalent Ca, one Fe, and one Si atom. In the twentieth O site, O is bonded in a bent 150 degrees geometry to two equivalent Ca, one Fe, and one Si atom. In the twenty-first O site, O is bonded in a distorted trigonal planar geometry to two Ca and one Si atom. In the twenty-second O site, O is bonded in a distorted trigonal planar geometry to two Ca and one Si atom. In the twenty-third O site, O is bonded in a distorted trigonal planar geometry to two Ca and one Si atom. In the twenty-fourth O site, O is bonded in a distorted trigonal planar geometry to two Ca and one Si atom. In the twenty-fifth O site, O is bonded in a 3-coordinate geometry to two equivalent Al and one Si atom. In the twenty-sixth O site, O is bonded in a 3-coordinate geometry to two equivalent Al and one Si atom. In the twenty-seventh O site, O is bonded in a 3-coordinate geometry to two equivalent Al and one Si atom. In the twenty-eighth O site, O is bonded in a 3-coordinate geometry to two equivalent Al and one Si atom. In the twenty-ninth O site, O is bonded to one Ca, two Al, and one Si atom to form a mixture of distorted corner and edge-sharing OCaAl2Si tetrahedra. In the thirtieth O site, O is bonded to one Ca, one Fe, one Al, and one Si atom to form a mixture of distorted corner and edge-sharing OCaAlFeSi tetrahedra. In the thirty-first O site, O is bonded to one Ca, one Fe, one Al, and one Si atom to form a mixture of distorted corner and edge-sharing OCaAlFeSi tetrahedra. In the thirty-second O site, O is bonded to one Ca, one Fe, one Al, and one Si atom to form distorted OCaAlFeSi tetrahedra that share corners with two OCaAl2Si tetrahedra and an edgeedge with one OCaAlFeSi tetrahedra. In the thirty-third O site, O is bonded in a 4-coordinate geometry to two Ca, one Al, and one Si atom. In the thirty-fourth O site, O is bonded in a 4-coordinate geometry to two Ca, one Al, and one Si atom. In the thirty-fifth O site, O is bonded in a 4-coordinate geometry to two Ca, one Al, and one Si atom. In the thirty-sixth O site, O is bonded in a 4-coordinate geometry to two Ca, one Al, and one Si atom. In the thirty-seventh O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the thirty-eighth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the thirty-ninth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the fortieth O sit

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg6Si5 by Materials Project

Mg6Si5 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are twelve inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a distorted trigonal non-coplanar geometry to three Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.82–2.98 Å. In the second Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.66–3.12 Å. In the third Mg2+ site, Mg2+ is bonded in a 4-coordinate geometry to eight Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.67–3.22 Å. In the fourth Mg2+ site, Mg2+ is bonded to four Si+2.40- atoms to form a mixture of distorted edge and corner-sharing MgSi4 tetrahedra. There are a spread of Mg–Si bond distances ranging from 2.80–2.91 Å. In the fifth Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.75–2.94 Å. In the sixth Mg2+ site, Mg2+ is bonded in a 1-coordinate geometry to four Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.68–3.17 Å. In the seventh Mg2+ site, Mg2+ is bonded in a 7-coordinate geometry to seven Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.65–2.93 Å. In the eighth Mg2+ site, Mg2+ is bonded in a 7-coordinate geometry to seven Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.78–3.25 Å. In the ninth Mg2+ site, Mg2+ is bonded to four Si+2.40- atoms to form a mixture of distorted edge and corner-sharing MgSi4 tetrahedra. There are a spread of Mg–Si bond distances ranging from 2.60–2.79 Å. In the tenth Mg2+ site, Mg2+ is bonded in a 1-coordinate geometry to six Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.69–3.14 Å. In the eleventh Mg2+ site, Mg2+ is bonded in a 3-coordinate geometry to four Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.65–3.17 Å. In the twelfth Mg2+ site, Mg2+ is bonded in a trigonal non-coplanar geometry to three Si+2.40- atoms. There are one shorter (2.70 Å) and two longer (2.78 Å) Mg–Si bond lengths. There are ten inequivalent Si+2.40- sites. In the first Si+2.40- site, Si+2.40- is bonded in a 8-coordinate geometry to seven Mg2+ and one Si+2.40- atom. The Si–Si bond length is 2.40 Å. In the second Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to six Mg2+ and three Si+2.40- atoms. There are a spread of Si–Si bond distances ranging from 2.43–2.53 Å. In the third Si+2.40- site, Si+2.40- is bonded in a 2-coordinate geometry to six Mg2+ and two equivalent Si+2.40- atoms. In the fourth Si+2.40- site, Si+2.40- is bonded in a 7-coordinate geometry to six Mg2+ and one Si+2.40- atom. The Si–Si bond length is 2.54 Å. In the fifth Si+2.40- site, Si+2.40- is bonded in a 7-coordinate geometry to five Mg2+ and two Si+2.40- atoms. The Si–Si bond length is 2.40 Å. In the sixth Si+2.40- site, Si+2.40- is bonded in a 8-coordinate geometry to five Mg2+ and three Si+2.40- atoms. The Si–Si bond length is 2.41 Å. In the seventh Si+2.40- site, Si+2.40- is bonded in a 8-coordinate geometry to seven Mg2+ and one Si+2.40- atom. The Si–Si bond length is 2.42 Å. In the eighth Si+2.40- site, Si+2.40- is bonded in a 1-coordinate geometry to six Mg2+ and three Si+2.40- atoms. The Si–Si bond length is 2.41 Å. In the ninth Si+2.40- site, Si+2.40- is bonded in a 7-coordinate geometry to seven Mg2+ atoms. In the tenth Si+2.40- site, Si+2.40- is bonded in a 6-coordinate geometry to six Mg2+ and two Si+2.40- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca8Al9Fe3Si12(HO13)4 by Materials Project

Ca8Fe3Al9Si12(HO13)4 crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are eight inequivalent Ca sites. In the first Ca site, Ca is bonded in a 1-coordinate geometry to eight O atoms. There are a spread of Ca–O bond distances ranging from 2.26–2.86 Å. In the second Ca site, Ca is bonded in a 1-coordinate geometry to ten O atoms. There are a spread of Ca–O bond distances ranging from 2.27–3.05 Å. In the third Ca site, Ca is bonded in a 1-coordinate geometry to ten O atoms. There are a spread of Ca–O bond distances ranging from 2.26–3.05 Å. In the fourth Ca site, Ca is bonded in a 1-coordinate geometry to ten O atoms. There are a spread of Ca–O bond distances ranging from 2.26–3.05 Å. In the fifth Ca site, Ca is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Ca–O bond distances ranging from 2.30–2.60 Å. In the sixth Ca site, Ca is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Ca–O bond distances ranging from 2.31–2.59 Å. In the seventh Ca site, Ca is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Ca–O bond distances ranging from 2.32–2.59 Å. In the eighth Ca site, Ca is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Ca–O bond distances ranging from 2.31–2.59 Å. There are three inequivalent Fe sites. In the first Fe site, Fe is bonded to six O atoms to form FeO6 octahedra that share corners with five SiO4 tetrahedra and edges with two equivalent AlO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.90–2.25 Å. In the second Fe site, Fe is bonded to six O atoms to form FeO6 octahedra that share corners with five SiO4 tetrahedra and edges with two equivalent AlO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.91–2.26 Å. In the third Fe site, Fe is bonded to six O atoms to form FeO6 octahedra that share corners with five SiO4 tetrahedra and edges with two equivalent AlO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.90–2.25 Å. There are five inequivalent Al sites. In the first Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with four SiO4 tetrahedra and edges with two equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–1.96 Å. In the second Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with four SiO4 tetrahedra and edges with two equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–1.95 Å. In the third Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with four SiO4 tetrahedra, edges with two FeO6 octahedra, and edges with two equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.86–1.98 Å. In the fourth Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with four SiO4 tetrahedra, an edgeedge with one FeO6 octahedra, and edges with three AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.86–1.98 Å. In the fifth Al site, Al is bonded to six O atoms to form distorted AlO6 octahedra that share corners with five SiO4 tetrahedra and edges with two equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.82–2.26 Å. There are twelve inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with six AlO6 octahedra. The corner-sharing octahedra tilt angles range from 48–54°. There are a spread of Si–O bond distances ranging from 1.65–1.68 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent FeO6 octahedra and corners with four AlO6 octahedra. The corner-sharing octahedra tilt angles range from 48–53°. There are a spread of Si–O bond distances ranging from 1.64–1.68 Å. In the third Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent FeO6 octahedra and corners with four AlO6 octahedra. The corner-sharing octahedra tilt angles range from 48–53°. There are a spread of Si–O bond distances ranging from 1.64–1.69 Å. In the fourth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent FeO6 octahedra and corners with four AlO6 octahedra. The corner-sharing octahedra tilt angles range from 48–53°. There are a spread of Si–O bond distances ranging from 1.64–1.68 Å. In the fifth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three AlO6 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 30–53°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the sixth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one FeO6 octahedra, corners with two equivalent AlO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 36–54°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the seventh Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one FeO6 octahedra, corners with two equivalent AlO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 36–54°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the eighth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one FeO6 octahedra, corners with two equivalent AlO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 36–54°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the ninth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with four AlO6 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–57°. There are a spread of Si–O bond distances ranging from 1.59–1.67 Å. In the tenth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent FeO6 octahedra, corners with two equivalent AlO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–56°. There are a spread of Si–O bond distances ranging from 1.59–1.67 Å. In the eleventh Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent FeO6 octahedra, corners with two equivalent AlO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 55°. There are a spread of Si–O bond distances ranging from 1.59–1.67 Å. In the twelfth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent FeO6 octahedra, corners with two equivalent AlO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–56°. There are a spread of Si–O bond distances ranging from 1.59–1.67 Å. There are three inequivalent H sites. In the first H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.99 Å. In the second H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.99 Å. In the third H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.99 Å. There are forty inequivalent O sites. In the first O site, O is bonded to one Ca, two Al, and one Si atom to form a mixture of distorted edge and corner-sharing OCaAl2Si tetrahedra. In the second O site, O is bonded to one Ca, one Fe, one Al, and one Si atom to form a mixture of distorted edge and corner-sharing OCaAlFeSi tetrahedra. In the third O site, O is bonded to one Ca, one Fe, one Al, and one Si atom to form distorted OCaAlFeSi tetrahedra that share corners with two OCaAl2Si tetrahedra and an edgeedge with one OCaAlFeSi tetrahedra. In the fourth O site, O is bonded to one Ca, one Fe, one Al, and one Si atom to form a mixture of distorted edge and corner-sharing OCaAlFeSi tetrahedra. In the fifth O site, O is bonded in a distorted single-bond geometry to one Ca, two equivalent Al, and one H atom. In the sixth O site, O is bonded in a distorted single-bond geometry to one Ca, two equivalent Al, and one H atom. In the seventh O site, O is bonded in a distorted single-bond geometry to one Ca, two equivalent Al, and one H atom. In the eighth O site, O is bonded in a distorted single-bond geometry to one Ca, two equivalent Al, and one H atom. The O–H bond length is 0.99 Å. In the ninth O site, O is bonded in a 3-coordinate geometry to two equivalent Al and one Si atom. In the tenth O site, O is bonded in a 3-coordinate geometry to two equivalent Al and one Si atom. In the eleventh O site, O is bonded in a 3-coordinate geometry to two equivalent Al and one Si atom. In the twelfth O site, O is bonded in a 3-coordinate geometry to two equivalent Al and one Si atom. In the thirteenth O site, O is bonded in a bent 150 degrees geometry to one Al and one Si atom. In the fourteenth O site, O is bonded in a bent 150 degrees geometry to two equivalent Ca, one Fe, and one Si atom. In the fifteenth O site, O is bonded in a distorted bent 150 degrees geometry to two equivalent Ca, one Fe, and one Si atom. In the sixteenth O site, O is bonded in a bent 150 degrees geometry to two equivalent Ca, one Fe, and one Si atom. In the seventeenth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the eighteenth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the nineteenth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the twentieth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the twenty-first O site, O is bonded in a distorted trigonal planar geometry to two Ca and one Si atom. In the twenty-second O site, O is bonded in a distorted trigonal planar geometry to two Ca and one Si atom. In the twenty-third O site, O is bonded in a distorted trigonal planar geometry to two Ca and one Si atom. In the twenty-fourth O site, O is bonded in a distorted trigonal planar geometry to two Ca and one Si atom. In the twenty-fifth O site, O is bonded in a trigonal non-coplanar geometry to three Al atoms. In the twenty-sixth O site, O is bonded in a trigonal non-coplanar geometry to one Fe and two equivalent Al atoms. In the twenty-seventh O site, O is bonded in a trigonal non-coplanar geometry to one Fe and two equivalent Al atoms. In the twenty-eighth O site, O is bonded in a trigonal non-coplanar geometry to one Fe and two equivalent Al atoms. In the twenty-ninth O site, O is bonded in a 2-coordinate geometry to two Ca, one Al, and one Si atom. In the thirtieth O site, O is bonded in a 4-coordinate geometry to two Ca, one Fe, and one Si atom. In the thirty-first O site, O is bonded in a 4-coordinate geometry to two Ca, one Fe, and one Si atom. In the thirty-second O site, O is bonded in a 4-coordinate geometry to two Ca, one Fe, and one Si atom. In the thirty-third O site, O is bonded in a 4-coordinate geometry to two Ca, one Al, and one Si atom. In the thirty-fourth O site, O is bonded in a 4-coordinate geometry to two Ca, one Al, and one Si atom. In the thirty-fifth O site, O is bonded in a 4-coordinate geometry to two Ca, one Al, and one Si atom. In the thirty-sixth O site, O is bonded in a 4-coordinate geometry to two Ca, one Al, and one Si atom. In the thirty-seventh O site, O is bonded in a 4-coordinate geometry to one Ca, two equivalent Al, and one Si atom. In the thirty-eighth O site, O is bonded in a 4-coordinate geometry to one Ca, two equivalent Al, and one Si atom. In the thirty-ninth O site, O is bonded in a 4-coordinate geometry to one Ca, two equivalent Al, and one Si atom. In the fortieth O site, O is bonded in a 4-coordinat

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg9Si5 by Materials Project

Mg9Si5 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eighteen inequivalent Mg sites. In the first Mg site, Mg is bonded in a 4-coordinate geometry to one Mg and four Si atoms. The Mg–Mg bond length is 2.97 Å. There are a spread of Mg–Si bond distances ranging from 2.64–2.88 Å. In the second Mg site, Mg is bonded in a 4-coordinate geometry to one Mg and four Si atoms. The Mg–Mg bond length is 3.06 Å. There are a spread of Mg–Si bond distances ranging from 2.78–2.98 Å. In the third Mg site, Mg is bonded in a 4-coordinate geometry to four Si atoms. There are a spread of Mg–Si bond distances ranging from 2.66–3.02 Å. In the fourth Mg site, Mg is bonded in a 4-coordinate geometry to seven Mg and four Si atoms. There are a spread of Mg–Mg bond distances ranging from 2.92–3.17 Å. There are a spread of Mg–Si bond distances ranging from 2.79–3.10 Å. In the fifth Mg site, Mg is bonded in a 4-coordinate geometry to four Si atoms. There are a spread of Mg–Si bond distances ranging from 2.75–3.03 Å. In the sixth Mg site, Mg is bonded in a 5-coordinate geometry to one Mg and five Si atoms. There are a spread of Mg–Si bond distances ranging from 2.72–2.94 Å. In the seventh Mg site, Mg is bonded in a 2-coordinate geometry to five Mg and six Si atoms. There are a spread of Mg–Mg bond distances ranging from 2.94–3.30 Å. There are a spread of Mg–Si bond distances ranging from 2.74–3.17 Å. In the eighth Mg site, Mg is bonded in a distorted tetrahedral geometry to one Mg and four Si atoms. There are a spread of Mg–Si bond distances ranging from 2.75–2.88 Å. In the ninth Mg site, Mg is bonded in a 5-coordinate geometry to one Mg and five Si atoms. There are a spread of Mg–Si bond distances ranging from 2.70–3.00 Å. In the tenth Mg site, Mg is bonded in a 4-coordinate geometry to one Mg and four Si atoms. There are a spread of Mg–Si bond distances ranging from 2.66–2.95 Å. In the eleventh Mg site, Mg is bonded in a 5-coordinate geometry to five Si atoms. There are a spread of Mg–Si bond distances ranging from 2.72–2.99 Å. In the twelfth Mg site, Mg is bonded in a 4-coordinate geometry to one Mg and four Si atoms. There are a spread of Mg–Si bond distances ranging from 2.79–2.90 Å. In the thirteenth Mg site, Mg is bonded in a 4-coordinate geometry to one Mg and four Si atoms. There are a spread of Mg–Si bond distances ranging from 2.73–3.06 Å. In the fourteenth Mg site, Mg is bonded in a 5-coordinate geometry to five Si atoms. There are a spread of Mg–Si bond distances ranging from 2.82–2.96 Å. In the fifteenth Mg site, Mg is bonded in a 5-coordinate geometry to two Mg and five Si atoms. There are a spread of Mg–Si bond distances ranging from 2.81–3.08 Å. In the sixteenth Mg site, Mg is bonded in a 5-coordinate geometry to five Si atoms. There are a spread of Mg–Si bond distances ranging from 2.76–2.97 Å. In the seventeenth Mg site, Mg is bonded in a 4-coordinate geometry to two Mg and five Si atoms. There are a spread of Mg–Si bond distances ranging from 2.68–3.04 Å. In the eighteenth Mg site, Mg is bonded in a 4-coordinate geometry to four Si atoms. There are a spread of Mg–Si bond distances ranging from 2.75–3.01 Å. There are ten inequivalent Si sites. In the first Si site, Si is bonded in a 10-coordinate geometry to nine Mg and one Si atom. The Si–Si bond length is 2.68 Å. In the second Si site, Si is bonded in a 8-coordinate geometry to eight Mg atoms. In the third Si site, Si is bonded in a 1-coordinate geometry to seven Mg and one Si atom. The Si–Si bond length is 2.49 Å. In the fourth Si site, Si is bonded in a 9-coordinate geometry to seven Mg and two Si atoms. In the fifth Si site, Si is bonded in a 9-coordinate geometry to nine Mg atoms. In the sixth Si site, Si is bonded in a 9-coordinate geometry to nine Mg atoms. In the seventh Si site, Si is bonded in a 9-coordinate geometry to nine Mg atoms. In the eighth Si site, Si is bonded in a 8-coordinate geometry to eight Mg atoms. In the ninth Si site, Si is bonded in a 9-coordinate geometry to eight Mg and one Si atom. The Si–Si bond length is 2.41 Å. In the tenth Si site, Si is bonded in a 9-coordinate geometry to seven Mg and one Si atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg6Si5 by Materials Project

Mg6Si5 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are twelve inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a bent 150 degrees geometry to two Si+2.40- atoms. There are one shorter (2.85 Å) and one longer (2.93 Å) Mg–Si bond lengths. In the second Mg2+ site, Mg2+ is bonded in a rectangular see-saw-like geometry to four Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.59–2.72 Å. In the third Mg2+ site, Mg2+ is bonded in a 7-coordinate geometry to seven Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.73–2.99 Å. In the fourth Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.75–3.01 Å. In the fifth Mg2+ site, Mg2+ is bonded in a see-saw-like geometry to four Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.69–3.00 Å. In the sixth Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.76–3.13 Å. In the seventh Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.74–3.16 Å. In the eighth Mg2+ site, Mg2+ is bonded in a 4-coordinate geometry to four Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.74–2.96 Å. In the ninth Mg2+ site, Mg2+ is bonded in a 1-coordinate geometry to two Si+2.40- atoms. There are one shorter (2.62 Å) and one longer (2.87 Å) Mg–Si bond lengths. In the tenth Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.74–2.96 Å. In the eleventh Mg2+ site, Mg2+ is bonded in a single-bond geometry to one Si+2.40- atom. The Mg–Si bond length is 2.66 Å. In the twelfth Mg2+ site, Mg2+ is bonded in a 3-coordinate geometry to three Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.67–3.08 Å. There are ten inequivalent Si+2.40- sites. In the first Si+2.40- site, Si+2.40- is bonded in a 7-coordinate geometry to five Mg2+ and two Si+2.40- atoms. There are one shorter (2.36 Å) and one longer (2.47 Å) Si–Si bond lengths. In the second Si+2.40- site, Si+2.40- is bonded in a 7-coordinate geometry to five Mg2+ and two Si+2.40- atoms. The Si–Si bond length is 2.41 Å. In the third Si+2.40- site, Si+2.40- is bonded in a 8-coordinate geometry to five Mg2+ and three Si+2.40- atoms. There are a spread of Si–Si bond distances ranging from 2.43–2.69 Å. In the fourth Si+2.40- site, Si+2.40- is bonded in a 7-coordinate geometry to five Mg2+ and two Si+2.40- atoms. There are one shorter (2.35 Å) and one longer (2.49 Å) Si–Si bond lengths. In the fifth Si+2.40- site, Si+2.40- is bonded in a 6-coordinate geometry to three Mg2+ and three Si+2.40- atoms. There are one shorter (2.38 Å) and one longer (2.42 Å) Si–Si bond lengths. In the sixth Si+2.40- site, Si+2.40- is bonded in a 8-coordinate geometry to six Mg2+ and two Si+2.40- atoms. There are one shorter (2.41 Å) and one longer (2.54 Å) Si–Si bond lengths. In the seventh Si+2.40- site, Si+2.40- is bonded in a 8-coordinate geometry to six Mg2+ and two Si+2.40- atoms. In the eighth Si+2.40- site, Si+2.40- is bonded in a 2-coordinate geometry to four Mg2+ and two Si+2.40- atoms. In the ninth Si+2.40- site, Si+2.40- is bonded in a 6-coordinate geometry to four Mg2+ and two Si+2.40- atoms. In the tenth Si+2.40- site, Si+2.40- is bonded in a 8-coordinate geometry to four Mg2+ and four Si+2.40- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg6Si5 by Materials Project

Mg6Si5 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are twelve inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a 3-coordinate geometry to four Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.59–3.10 Å. In the second Mg2+ site, Mg2+ is bonded in a rectangular see-saw-like geometry to four Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.69–2.76 Å. In the third Mg2+ site, Mg2+ is bonded in a distorted hexagonal planar geometry to six Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.85–3.03 Å. In the fourth Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.80–3.17 Å. In the fifth Mg2+ site, Mg2+ is bonded in a trigonal non-coplanar geometry to three Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.60–2.75 Å. In the sixth Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to five Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.82–3.24 Å. In the seventh Mg2+ site, Mg2+ is bonded in a 2-coordinate geometry to nine Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.76–3.28 Å. In the eighth Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.76–3.05 Å. In the ninth Mg2+ site, Mg2+ is bonded in a 3-coordinate geometry to three Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.73–2.89 Å. In the tenth Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.82–3.06 Å. In the eleventh Mg2+ site, Mg2+ is bonded in a bent 120 degrees geometry to two Si+2.40- atoms. There are one shorter (2.77 Å) and one longer (2.83 Å) Mg–Si bond lengths. In the twelfth Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.60–2.91 Å. There are ten inequivalent Si+2.40- sites. In the first Si+2.40- site, Si+2.40- is bonded in a 8-coordinate geometry to six Mg2+ and two Si+2.40- atoms. There are one shorter (2.42 Å) and one longer (2.44 Å) Si–Si bond lengths. In the second Si+2.40- site, Si+2.40- is bonded in a 8-coordinate geometry to six Mg2+ and two Si+2.40- atoms. The Si–Si bond length is 2.41 Å. In the third Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to six Mg2+ and three Si+2.40- atoms. There are a spread of Si–Si bond distances ranging from 2.50–2.54 Å. In the fourth Si+2.40- site, Si+2.40- is bonded in a 7-coordinate geometry to six Mg2+ and one Si+2.40- atom. The Si–Si bond length is 2.52 Å. In the fifth Si+2.40- site, Si+2.40- is bonded in a 8-coordinate geometry to six Mg2+ and two Si+2.40- atoms. There are one shorter (2.44 Å) and one longer (2.45 Å) Si–Si bond lengths. In the sixth Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to six Mg2+ and three Si+2.40- atoms. There are a spread of Si–Si bond distances ranging from 2.48–2.69 Å. In the seventh Si+2.40- site, Si+2.40- is bonded in a 10-coordinate geometry to seven Mg2+ and three Si+2.40- atoms. In the eighth Si+2.40- site, Si+2.40- is bonded in a 7-coordinate geometry to five Mg2+ and two Si+2.40- atoms. In the ninth Si+2.40- site, Si+2.40- is bonded in a 8-coordinate geometry to six Mg2+ and two Si+2.40- atoms. In the tenth Si+2.40- site, Si+2.40- is bonded in a 8-coordinate geometry to five Mg2+ and four Si+2.40- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg6Si5 by Materials Project

Mg6Si5 crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are twelve inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a single-bond geometry to one Si+2.40- atom. The Mg–Si bond length is 2.84 Å. In the second Mg2+ site, Mg2+ is bonded in a rectangular see-saw-like geometry to four Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.65–2.90 Å. In the third Mg2+ site, Mg2+ is bonded in a 8-coordinate geometry to eight Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.83–3.09 Å. In the fourth Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to eight Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.77–3.15 Å. In the fifth Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.87–3.04 Å. In the sixth Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.97–3.14 Å. In the seventh Mg2+ site, Mg2+ is bonded in a 8-coordinate geometry to eight Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.90–2.98 Å. In the eighth Mg2+ site, Mg2+ is bonded in a 8-coordinate geometry to eight Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.76–3.03 Å. In the ninth Mg2+ site, Mg2+ is bonded in a distorted T-shaped geometry to three Si+2.40- atoms. There are two shorter (2.83 Å) and one longer (2.91 Å) Mg–Si bond lengths. In the tenth Mg2+ site, Mg2+ is bonded in a 4-coordinate geometry to five Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.80–3.09 Å. In the eleventh Mg2+ site, Mg2+ is bonded in a linear geometry to two Si+2.40- atoms. There are one shorter (2.72 Å) and one longer (2.83 Å) Mg–Si bond lengths. In the twelfth Mg2+ site, Mg2+ is bonded in a 4-coordinate geometry to four Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.91–3.11 Å. There are ten inequivalent Si+2.40- sites. In the first Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to seven Mg2+ and two Si+2.40- atoms. There are one shorter (2.37 Å) and one longer (2.46 Å) Si–Si bond lengths. In the second Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to seven Mg2+ and two Si+2.40- atoms. The Si–Si bond length is 2.40 Å. In the third Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to six Mg2+ and three Si+2.40- atoms. There are two shorter (2.47 Å) and one longer (2.70 Å) Si–Si bond lengths. In the fourth Si+2.40- site, Si+2.40- is bonded in a 8-coordinate geometry to four Mg2+ and four Si+2.40- atoms. There are a spread of Si–Si bond distances ranging from 2.37–2.63 Å. In the fifth Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to seven Mg2+ and two Si+2.40- atoms. The Si–Si bond length is 2.59 Å. In the sixth Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to six Mg2+ and three Si+2.40- atoms. There are one shorter (2.53 Å) and two longer (2.54 Å) Si–Si bond lengths. In the seventh Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to six Mg2+ and three Si+2.40- atoms. In the eighth Si+2.40- site, Si+2.40- is bonded in a 10-coordinate geometry to seven Mg2+ and three Si+2.40- atoms. In the ninth Si+2.40- site, Si+2.40- is bonded in a 8-coordinate geometry to six Mg2+ and two equivalent Si+2.40- atoms. In the tenth Si+2.40- site, Si+2.40- is bonded in a 10-coordinate geometry to six Mg2+ and four Si+2.40- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg2Si3 by Materials Project

Mg2Si3 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eight inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.68–3.02 Å. In the second Mg2+ site, Mg2+ is bonded in a 8-coordinate geometry to eight Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.71–3.09 Å. In the third Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.76–3.06 Å. In the fourth Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.68–3.06 Å. In the fifth Mg2+ site, Mg2+ is bonded in a 7-coordinate geometry to seven Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.65–3.02 Å. In the sixth Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.84–2.98 Å. In the seventh Mg2+ site, Mg2+ is bonded in a 4-coordinate geometry to six Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.66–3.15 Å. In the eighth Mg2+ site, Mg2+ is bonded to seven Si+1.33- atoms to form a mixture of distorted corner and edge-sharing MgSi7 pentagonal bipyramids. There are a spread of Mg–Si bond distances ranging from 2.92–3.11 Å. There are twelve inequivalent Si+1.33- sites. In the first Si+1.33- site, Si+1.33- is bonded in a 7-coordinate geometry to four Mg2+ and three Si+1.33- atoms. There are two shorter (2.40 Å) and one longer (2.51 Å) Si–Si bond lengths. In the second Si+1.33- site, Si+1.33- is bonded in a 6-coordinate geometry to three Mg2+ and three Si+1.33- atoms. There are one shorter (2.38 Å) and one longer (2.42 Å) Si–Si bond lengths. In the third Si+1.33- site, Si+1.33- is bonded in a 6-coordinate geometry to three Mg2+ and three Si+1.33- atoms. The Si–Si bond length is 2.39 Å. In the fourth Si+1.33- site, Si+1.33- is bonded in a 6-coordinate geometry to three Mg2+ and three Si+1.33- atoms. The Si–Si bond length is 2.40 Å. In the fifth Si+1.33- site, Si+1.33- is bonded in a 7-coordinate geometry to five Mg2+ and two Si+1.33- atoms. There are one shorter (2.32 Å) and one longer (2.42 Å) Si–Si bond lengths. In the sixth Si+1.33- site, Si+1.33- is bonded in a 7-coordinate geometry to four Mg2+ and three Si+1.33- atoms. There are one shorter (2.39 Å) and two longer (2.40 Å) Si–Si bond lengths. In the seventh Si+1.33- site, Si+1.33- is bonded in a 7-coordinate geometry to four Mg2+ and three Si+1.33- atoms. There are a spread of Si–Si bond distances ranging from 2.38–2.42 Å. In the eighth Si+1.33- site, Si+1.33- is bonded in a 2-coordinate geometry to three Mg2+ and three Si+1.33- atoms. In the ninth Si+1.33- site, Si+1.33- is bonded in a 7-coordinate geometry to five Mg2+ and two Si+1.33- atoms. In the tenth Si+1.33- site, Si+1.33- is bonded in a 6-coordinate geometry to four Mg2+ and two equivalent Si+1.33- atoms. In the eleventh Si+1.33- site, Si+1.33- is bonded in a 7-coordinate geometry to six Mg2+ and one Si+1.33- atom. In the twelfth Si+1.33- site, Si+1.33- is bonded in a 8-coordinate geometry to six Mg2+ and two Si+1.33- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg6Si5 by Materials Project

Mg6Si5 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are twelve inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a distorted trigonal non-coplanar geometry to four Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.68–3.23 Å. In the second Mg2+ site, Mg2+ is bonded in a rectangular see-saw-like geometry to four Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.71–2.75 Å. In the third Mg2+ site, Mg2+ is bonded in a 4-coordinate geometry to six Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.83–3.12 Å. In the fourth Mg2+ site, Mg2+ is bonded to six Si+2.40- atoms to form distorted edge-sharing MgSi6 octahedra. There are a spread of Mg–Si bond distances ranging from 2.89–2.95 Å. In the fifth Mg2+ site, Mg2+ is bonded in a 3-coordinate geometry to five Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.57–3.19 Å. In the sixth Mg2+ site, Mg2+ is bonded in a 3-coordinate geometry to seven Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.79–3.25 Å. In the seventh Mg2+ site, Mg2+ is bonded in a 9-coordinate geometry to nine Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.98–3.20 Å. In the eighth Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to six Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.65–3.25 Å. In the ninth Mg2+ site, Mg2+ is bonded in a trigonal non-coplanar geometry to three Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.65–2.81 Å. In the tenth Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.87–3.05 Å. In the eleventh Mg2+ site, Mg2+ is bonded in a trigonal non-coplanar geometry to three Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.73–2.91 Å. In the twelfth Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.62–3.14 Å. There are ten inequivalent Si+2.40- sites. In the first Si+2.40- site, Si+2.40- is bonded in a 7-coordinate geometry to five Mg2+ and two Si+2.40- atoms. Both Si–Si bond lengths are 2.43 Å. In the second Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to seven Mg2+ and two Si+2.40- atoms. The Si–Si bond length is 2.37 Å. In the third Si+2.40- site, Si+2.40- is bonded in a 2-coordinate geometry to seven Mg2+ and three Si+2.40- atoms. There are a spread of Si–Si bond distances ranging from 2.48–2.54 Å. In the fourth Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to eight Mg2+ and one Si+2.40- atom. The Si–Si bond length is 2.61 Å. In the fifth Si+2.40- site, Si+2.40- is bonded in a 5-coordinate geometry to seven Mg2+ and two Si+2.40- atoms. There are one shorter (2.55 Å) and one longer (2.66 Å) Si–Si bond lengths. In the sixth Si+2.40- site, Si+2.40- is bonded in a 2-coordinate geometry to seven Mg2+ and three Si+2.40- atoms. There are a spread of Si–Si bond distances ranging from 2.49–2.58 Å. In the seventh Si+2.40- site, Si+2.40- is bonded in a 2-coordinate geometry to seven Mg2+ and three Si+2.40- atoms. In the eighth Si+2.40- site, Si+2.40- is bonded in a 8-coordinate geometry to six Mg2+ and two Si+2.40- atoms. In the ninth Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to seven Mg2+ and two Si+2.40- atoms. In the tenth Si+2.40- site, Si+2.40- is bonded in a 8-coordinate geometry to four Mg2+ and four Si+2.40- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg6Si5 by Materials Project

Mg6Si5 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are twelve inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a 2-coordinate geometry to three Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.75–2.91 Å. In the second Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to seven Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.78–3.18 Å. In the third Mg2+ site, Mg2+ is bonded in a 1-coordinate geometry to eight Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.66–3.21 Å. In the fourth Mg2+ site, Mg2+ is bonded in a 9-coordinate geometry to ten Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.75–3.27 Å. In the fifth Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.77–3.13 Å. In the sixth Mg2+ site, Mg2+ is bonded in a 4-coordinate geometry to five Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.77–3.19 Å. In the seventh Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.74–3.17 Å. In the eighth Mg2+ site, Mg2+ is bonded in a 8-coordinate geometry to eight Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.84–3.20 Å. In the ninth Mg2+ site, Mg2+ is bonded in a 3-coordinate geometry to three Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.99–3.19 Å. In the tenth Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.82–3.04 Å. In the eleventh Mg2+ site, Mg2+ is bonded in a distorted L-shaped geometry to two Si+2.40- atoms. There are one shorter (2.75 Å) and one longer (2.86 Å) Mg–Si bond lengths. In the twelfth Mg2+ site, Mg2+ is bonded in a 4-coordinate geometry to four Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.84–3.18 Å. There are ten inequivalent Si+2.40- sites. In the first Si+2.40- site, Si+2.40- is bonded in a 10-coordinate geometry to eight Mg2+ and two Si+2.40- atoms. There are one shorter (2.55 Å) and one longer (2.72 Å) Si–Si bond lengths. In the second Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to six Mg2+ and three Si+2.40- atoms. There are one shorter (2.54 Å) and one longer (2.68 Å) Si–Si bond lengths. In the third Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to seven Mg2+ and two Si+2.40- atoms. There are one shorter (2.47 Å) and one longer (2.54 Å) Si–Si bond lengths. In the fourth Si+2.40- site, Si+2.40- is bonded in a 2-coordinate geometry to five Mg2+ and five Si+2.40- atoms. There are a spread of Si–Si bond distances ranging from 2.62–2.85 Å. In the fifth Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to six Mg2+ and three Si+2.40- atoms. There are one shorter (2.50 Å) and one longer (2.52 Å) Si–Si bond lengths. In the sixth Si+2.40- site, Si+2.40- is bonded in a 10-coordinate geometry to seven Mg2+ and three Si+2.40- atoms. There are one shorter (2.48 Å) and one longer (2.55 Å) Si–Si bond lengths. In the seventh Si+2.40- site, Si+2.40- is bonded in a 10-coordinate geometry to eight Mg2+ and two Si+2.40- atoms. In the eighth Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to seven Mg2+ and two Si+2.40- atoms. In the ninth Si+2.40- site, Si+2.40- is bonded in a 10-coordinate geometry to seven Mg2+ and three Si+2.40- atoms. In the tenth Si+2.40- site, Si+2.40- is bonded in a 2-coordinate geometry to five Mg2+ and three Si+2.40- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg6Si5 by Materials Project

Mg6Si5 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are twelve inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a linear geometry to two Si+2.40- atoms. There are one shorter (2.79 Å) and one longer (2.86 Å) Mg–Si bond lengths. In the second Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to six Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.78–3.26 Å. In the third Mg2+ site, Mg2+ is bonded in a 9-coordinate geometry to nine Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.81–3.10 Å. In the fourth Mg2+ site, Mg2+ is bonded in a 8-coordinate geometry to eight Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.75–3.14 Å. In the fifth Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.75–3.12 Å. In the sixth Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.83–3.11 Å. In the seventh Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.76–3.09 Å. In the eighth Mg2+ site, Mg2+ is bonded in a 8-coordinate geometry to eight Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.82–3.14 Å. In the ninth Mg2+ site, Mg2+ is bonded in a 1-coordinate geometry to three Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.78–3.17 Å. In the tenth Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.77–2.91 Å. In the eleventh Mg2+ site, Mg2+ is bonded in a single-bond geometry to one Si+2.40- atom. The Mg–Si bond length is 2.70 Å. In the twelfth Mg2+ site, Mg2+ is bonded to four Si+2.40- atoms to form distorted corner-sharing MgSi4 trigonal pyramids. There are a spread of Mg–Si bond distances ranging from 2.87–2.97 Å. There are ten inequivalent Si+2.40- sites. In the first Si+2.40- site, Si+2.40- is bonded in a 10-coordinate geometry to seven Mg2+ and three Si+2.40- atoms. There are a spread of Si–Si bond distances ranging from 2.69–2.85 Å. In the second Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to seven Mg2+ and two Si+2.40- atoms. The Si–Si bond length is 2.51 Å. In the third Si+2.40- site, Si+2.40- is bonded in a 2-coordinate geometry to six Mg2+ and three Si+2.40- atoms. There are a spread of Si–Si bond distances ranging from 2.52–2.86 Å. In the fourth Si+2.40- site, Si+2.40- is bonded in a 2-coordinate geometry to four Mg2+ and four Si+2.40- atoms. There are a spread of Si–Si bond distances ranging from 2.58–2.76 Å. In the fifth Si+2.40- site, Si+2.40- is bonded in a 8-coordinate geometry to five Mg2+ and three Si+2.40- atoms. There are one shorter (2.53 Å) and one longer (2.55 Å) Si–Si bond lengths. In the sixth Si+2.40- site, Si+2.40- is bonded in a 10-coordinate geometry to six Mg2+ and four Si+2.40- atoms. There are a spread of Si–Si bond distances ranging from 2.54–2.91 Å. In the seventh Si+2.40- site, Si+2.40- is bonded in a 8-coordinate geometry to six Mg2+ and three Si+2.40- atoms. In the eighth Si+2.40- site, Si+2.40- is bonded in a 10-coordinate geometry to seven Mg2+ and three Si+2.40- atoms. In the ninth Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to seven Mg2+ and two Si+2.40- atoms. In the tenth Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to six Mg2+ and three Si+2.40- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg2Si3 by Materials Project

Mg2Si3 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eight inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a 8-coordinate geometry to eight Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.79–3.06 Å. In the second Mg2+ site, Mg2+ is bonded in a 9-coordinate geometry to nine Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.80–3.05 Å. In the third Mg2+ site, Mg2+ is bonded in a 9-coordinate geometry to nine Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.75–3.02 Å. In the fourth Mg2+ site, Mg2+ is bonded in a 9-coordinate geometry to nine Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.78–3.02 Å. In the fifth Mg2+ site, Mg2+ is bonded in a 7-coordinate geometry to seven Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.70–3.08 Å. In the sixth Mg2+ site, Mg2+ is bonded in a 8-coordinate geometry to eight Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.77–3.10 Å. In the seventh Mg2+ site, Mg2+ is bonded in a 4-coordinate geometry to eight Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.75–3.16 Å. In the eighth Mg2+ site, Mg2+ is bonded in a 8-coordinate geometry to eight Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.73–3.12 Å. There are twelve inequivalent Si+1.33- sites. In the first Si+1.33- site, Si+1.33- is bonded in a 9-coordinate geometry to five Mg2+ and four Si+1.33- atoms. There are a spread of Si–Si bond distances ranging from 2.42–2.60 Å. In the second Si+1.33- site, Si+1.33- is bonded in a 9-coordinate geometry to five Mg2+ and four Si+1.33- atoms. There are one shorter (2.41 Å) and two longer (2.52 Å) Si–Si bond lengths. In the third Si+1.33- site, Si+1.33- is bonded in a 9-coordinate geometry to five Mg2+ and four Si+1.33- atoms. There are one shorter (2.44 Å) and one longer (2.49 Å) Si–Si bond lengths. In the fourth Si+1.33- site, Si+1.33- is bonded in a 9-coordinate geometry to five Mg2+ and four Si+1.33- atoms. In the fifth Si+1.33- site, Si+1.33- is bonded in a 9-coordinate geometry to six Mg2+ and three Si+1.33- atoms. There are a spread of Si–Si bond distances ranging from 2.42–2.55 Å. In the sixth Si+1.33- site, Si+1.33- is bonded in a 9-coordinate geometry to seven Mg2+ and two Si+1.33- atoms. There are one shorter (2.38 Å) and one longer (2.41 Å) Si–Si bond lengths. In the seventh Si+1.33- site, Si+1.33- is bonded in a 12-coordinate geometry to three Mg2+ and five Si+1.33- atoms. There are two shorter (2.58 Å) and one longer (2.70 Å) Si–Si bond lengths. In the eighth Si+1.33- site, Si+1.33- is bonded in a 12-coordinate geometry to five Mg2+ and five Si+1.33- atoms. There are a spread of Si–Si bond distances ranging from 2.49–2.67 Å. In the ninth Si+1.33- site, Si+1.33- is bonded in a 4-coordinate geometry to five Mg2+ and four Si+1.33- atoms. In the tenth Si+1.33- site, Si+1.33- is bonded in a 9-coordinate geometry to six Mg2+ and three Si+1.33- atoms. In the eleventh Si+1.33- site, Si+1.33- is bonded in a 9-coordinate geometry to seven Mg2+ and two Si+1.33- atoms. In the twelfth Si+1.33- site, Si+1.33- is bonded in a 9-coordinate geometry to seven Mg2+ and two Si+1.33- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg6Si5 by Materials Project

Mg6Si5 crystallizes in the triclinic P1 space group. The structure is two-dimensional and consists of one Mg6Si5 sheet oriented in the (0, 0, 1) direction. there are twelve inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a single-bond geometry to one Si+2.40- atom. The Mg–Si bond length is 2.70 Å. In the second Mg2+ site, Mg2+ is bonded in a square co-planar geometry to four Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.73–2.88 Å. In the third Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to eight Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.78–3.20 Å. In the fourth Mg2+ site, Mg2+ is bonded in a 8-coordinate geometry to eight Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.79–3.14 Å. In the fifth Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.90–3.13 Å. In the sixth Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.85–3.10 Å. In the seventh Mg2+ site, Mg2+ is bonded in a 8-coordinate geometry to eight Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.83–3.00 Å. In the eighth Mg2+ site, Mg2+ is bonded in a 8-coordinate geometry to eight Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.82–2.98 Å. In the ninth Mg2+ site, Mg2+ is bonded in a single-bond geometry to one Si+2.40- atom. The Mg–Si bond length is 2.91 Å. In the tenth Mg2+ site, Mg2+ is bonded in a 4-coordinate geometry to four Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.77–3.01 Å. In the eleventh Mg2+ site, Mg2+ is bonded in a 4-coordinate geometry to five Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.80–3.19 Å. In the twelfth Mg2+ site, Mg2+ is bonded in a single-bond geometry to one Si+2.40- atom. The Mg–Si bond length is 2.69 Å. There are ten inequivalent Si+2.40- sites. In the first Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to seven Mg2+ and two Si+2.40- atoms. There are one shorter (2.36 Å) and one longer (2.42 Å) Si–Si bond lengths. In the second Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to seven Mg2+ and two Si+2.40- atoms. The Si–Si bond length is 2.44 Å. In the third Si+2.40- site, Si+2.40- is bonded in a 1-coordinate geometry to six Mg2+ and three Si+2.40- atoms. There are two shorter (2.43 Å) and one longer (2.64 Å) Si–Si bond lengths. In the fourth Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to six Mg2+ and three Si+2.40- atoms. There are a spread of Si–Si bond distances ranging from 2.45–2.64 Å. In the fifth Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to six Mg2+ and three Si+2.40- atoms. There are a spread of Si–Si bond distances ranging from 2.48–2.53 Å. In the sixth Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to six Mg2+ and three Si+2.40- atoms. There are one shorter (2.53 Å) and two longer (2.54 Å) Si–Si bond lengths. In the seventh Si+2.40- site, Si+2.40- is bonded in a 8-coordinate geometry to five Mg2+ and three Si+2.40- atoms. In the eighth Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to six Mg2+ and three Si+2.40- atoms. In the ninth Si+2.40- site, Si+2.40- is bonded in a 10-coordinate geometry to six Mg2+ and four Si+2.40- atoms. In the tenth Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to five Mg2+ and four Si+2.40- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg6Si5 by Materials Project

Mg6Si5 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are twelve inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a trigonal planar geometry to three Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.64–2.75 Å. In the second Mg2+ site, Mg2+ is bonded in a rectangular see-saw-like geometry to four Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.77–2.86 Å. In the third Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.77–3.19 Å. In the fourth Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.82–3.11 Å. In the fifth Mg2+ site, Mg2+ is bonded in a 2-coordinate geometry to three Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.62–3.03 Å. In the sixth Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.83–3.01 Å. In the seventh Mg2+ site, Mg2+ is bonded in a 7-coordinate geometry to seven Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.90–3.12 Å. In the eighth Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to six Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.60–3.20 Å. In the ninth Mg2+ site, Mg2+ is bonded in a distorted trigonal non-coplanar geometry to three Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.69–2.79 Å. In the tenth Mg2+ site, Mg2+ is bonded in a 1-coordinate geometry to five Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.99–3.24 Å. In the eleventh Mg2+ site, Mg2+ is bonded in a trigonal non-coplanar geometry to three Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.70–3.03 Å. In the twelfth Mg2+ site, Mg2+ is bonded in a 7-coordinate geometry to seven Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.75–3.13 Å. There are ten inequivalent Si+2.40- sites. In the first Si+2.40- site, Si+2.40- is bonded in a 8-coordinate geometry to six Mg2+ and two Si+2.40- atoms. There are one shorter (2.43 Å) and one longer (2.46 Å) Si–Si bond lengths. In the second Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to seven Mg2+ and two Si+2.40- atoms. The Si–Si bond length is 2.38 Å. In the third Si+2.40- site, Si+2.40- is bonded in a 2-coordinate geometry to six Mg2+ and three Si+2.40- atoms. There are a spread of Si–Si bond distances ranging from 2.46–2.55 Å. In the fourth Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to eight Mg2+ and one Si+2.40- atom. The Si–Si bond length is 2.57 Å. In the fifth Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to seven Mg2+ and two Si+2.40- atoms. There are one shorter (2.47 Å) and one longer (2.58 Å) Si–Si bond lengths. In the sixth Si+2.40- site, Si+2.40- is bonded in a 2-coordinate geometry to five Mg2+ and three Si+2.40- atoms. There are a spread of Si–Si bond distances ranging from 2.47–2.51 Å. In the seventh Si+2.40- site, Si+2.40- is bonded in a 1-coordinate geometry to five Mg2+ and three Si+2.40- atoms. In the eighth Si+2.40- site, Si+2.40- is bonded in a 7-coordinate geometry to five Mg2+ and two Si+2.40- atoms. In the ninth Si+2.40- site, Si+2.40- is bonded in a 7-coordinate geometry to five Mg2+ and two Si+2.40- atoms. In the tenth Si+2.40- site, Si+2.40- is bonded in a 7-coordinate geometry to three Mg2+ and four Si+2.40- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg2Si3 by Materials Project

Mg2Si3 is Magnesium tetraboride-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eight inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.68–2.94 Å. In the second Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.68–2.93 Å. In the third Mg2+ site, Mg2+ is bonded in a 7-coordinate geometry to seven Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.85–3.04 Å. In the fourth Mg2+ site, Mg2+ is bonded to seven Si+1.33- atoms to form a mixture of distorted edge and corner-sharing MgSi7 pentagonal bipyramids. There are a spread of Mg–Si bond distances ranging from 2.85–3.04 Å. In the fifth Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.71–2.99 Å. In the sixth Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.71–2.98 Å. In the seventh Mg2+ site, Mg2+ is bonded in a 3-coordinate geometry to ten Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.83–3.15 Å. In the eighth Mg2+ site, Mg2+ is bonded in a 3-coordinate geometry to ten Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.83–3.16 Å. There are twelve inequivalent Si+1.33- sites. In the first Si+1.33- site, Si+1.33- is bonded in a 6-coordinate geometry to three Mg2+ and three Si+1.33- atoms. There are a spread of Si–Si bond distances ranging from 2.29–2.43 Å. In the second Si+1.33- site, Si+1.33- is bonded in a 8-coordinate geometry to five Mg2+ and three Si+1.33- atoms. There are a spread of Si–Si bond distances ranging from 2.39–2.44 Å. In the third Si+1.33- site, Si+1.33- is bonded in a 8-coordinate geometry to five Mg2+ and three Si+1.33- atoms. The Si–Si bond length is 2.39 Å. In the fourth Si+1.33- site, Si+1.33- is bonded in a 6-coordinate geometry to three Mg2+ and three Si+1.33- atoms. In the fifth Si+1.33- site, Si+1.33- is bonded in a 8-coordinate geometry to six Mg2+ and two Si+1.33- atoms. There are one shorter (2.41 Å) and one longer (2.44 Å) Si–Si bond lengths. In the sixth Si+1.33- site, Si+1.33- is bonded in a 8-coordinate geometry to six Mg2+ and two Si+1.33- atoms. There are one shorter (2.41 Å) and one longer (2.44 Å) Si–Si bond lengths. In the seventh Si+1.33- site, Si+1.33- is bonded in a 9-coordinate geometry to five Mg2+ and four Si+1.33- atoms. There are a spread of Si–Si bond distances ranging from 2.45–2.53 Å. In the eighth Si+1.33- site, Si+1.33- is bonded in a 9-coordinate geometry to five Mg2+ and four Si+1.33- atoms. There are a spread of Si–Si bond distances ranging from 2.45–2.54 Å. In the ninth Si+1.33- site, Si+1.33- is bonded in a 9-coordinate geometry to five Mg2+ and four Si+1.33- atoms. In the tenth Si+1.33- site, Si+1.33- is bonded in a 9-coordinate geometry to five Mg2+ and four Si+1.33- atoms. In the eleventh Si+1.33- site, Si+1.33- is bonded in a 7-coordinate geometry to five Mg2+ and two Si+1.33- atoms. In the twelfth Si+1.33- site, Si+1.33- is bonded in a 7-coordinate geometry to five Mg2+ and two Si+1.33- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg6Si5 by Materials Project

Mg6Si5 crystallizes in the triclinic P1 space group. The structure is two-dimensional and consists of one Mg6Si5 sheet oriented in the (0, 0, 1) direction. there are twelve inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a single-bond geometry to one Si+2.40- atom. The Mg–Si bond length is 2.81 Å. In the second Mg2+ site, Mg2+ is bonded in a rectangular see-saw-like geometry to four Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.68–2.93 Å. In the third Mg2+ site, Mg2+ is bonded in a 8-coordinate geometry to eight Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.80–3.20 Å. In the fourth Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to seven Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.86–3.18 Å. In the fifth Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.87–3.21 Å. In the sixth Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.76–3.04 Å. In the seventh Mg2+ site, Mg2+ is bonded in a 8-coordinate geometry to eight Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.86–3.05 Å. In the eighth Mg2+ site, Mg2+ is bonded in a 8-coordinate geometry to eight Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.84–3.07 Å. In the ninth Mg2+ site, Mg2+ is bonded in a single-bond geometry to one Si+2.40- atom. The Mg–Si bond length is 2.63 Å. In the tenth Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.82–3.17 Å. In the eleventh Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.87–3.18 Å. In the twelfth Mg2+ site, Mg2+ is bonded in a single-bond geometry to one Si+2.40- atom. The Mg–Si bond length is 2.84 Å. There are ten inequivalent Si+2.40- sites. In the first Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to seven Mg2+ and two Si+2.40- atoms. There are one shorter (2.35 Å) and one longer (2.37 Å) Si–Si bond lengths. In the second Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to seven Mg2+ and two Si+2.40- atoms. The Si–Si bond length is 2.39 Å. In the third Si+2.40- site, Si+2.40- is bonded in a 8-coordinate geometry to five Mg2+ and three Si+2.40- atoms. There are a spread of Si–Si bond distances ranging from 2.50–2.82 Å. In the fourth Si+2.40- site, Si+2.40- is bonded in a 1-coordinate geometry to six Mg2+ and three Si+2.40- atoms. There are a spread of Si–Si bond distances ranging from 2.42–2.62 Å. In the fifth Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to six Mg2+ and three Si+2.40- atoms. There are a spread of Si–Si bond distances ranging from 2.54–2.62 Å. In the sixth Si+2.40- site, Si+2.40- is bonded in a 10-coordinate geometry to seven Mg2+ and three Si+2.40- atoms. There are a spread of Si–Si bond distances ranging from 2.48–2.58 Å. In the seventh Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to six Mg2+ and three Si+2.40- atoms. In the eighth Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to six Mg2+ and three Si+2.40- atoms. In the ninth Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to five Mg2+ and four Si+2.40- atoms. In the tenth Si+2.40- site, Si+2.40- is bonded in a 10-coordinate geometry to six Mg2+ and four Si+2.40- atoms.

36 MATERIALS SCIENCE↗