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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 2.73–2.91 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 2.71–3.10 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 2.76–2.97 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 2.66–2.89 Å. In the fifth Mg2+ site, Mg2+ is bonded to five Si+1.33- atoms to form distorted edge-sharing MgSi5 trigonal bipyramids. There are a spread of Mg–Si bond distances ranging from 2.73–2.91 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 2.77–2.86 Å. In the seventh 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 2.76–3.09 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 2.71–3.08 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 two shorter (2.41 Å) and one longer (2.43 Å) Si–Si bond lengths. In the second Si+1.33- site, Si+1.33- is bonded in a 6-coordinate geometry to two Mg2+ and four Si+1.33- atoms. There are a spread of Si–Si bond distances ranging from 2.34–2.49 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 2.41 Å. In the fourth Si+1.33- site, Si+1.33- is bonded in a 5-coordinate geometry to two Mg2+ and three Si+1.33- atoms. The Si–Si bond length is 2.43 Å. In the fifth Si+1.33- site, Si+1.33- is bonded in a 7-coordinate geometry to six Mg2+ and one Si+1.33- atom. The Si–Si bond length is 2.42 Å. 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 (2.44 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 6-coordinate geometry to three Mg2+ and three Si+1.33- atoms. There are one shorter (2.40 Å) and two longer (2.43 Å) Si–Si bond lengths. 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. There are one shorter (2.42 Å) and one longer (2.43 Å) Si–Si bond lengths. In the ninth 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 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 7-coordinate geometry to five Mg2+ and two Si+1.33- 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 5-coordinate geometry to seven Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.84–3.18 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 2.73–2.97 Å. In the third Mg2+ site, Mg2+ is bonded to four Si+1.33- atoms to form distorted corner-sharing MgSi4 tetrahedra. There are a spread of Mg–Si bond distances ranging from 2.69–2.98 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 2.75–2.97 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 2.72–2.98 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 2.66–3.10 Å. In the seventh 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 2.73–2.95 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 2.74–2.96 Å. There are twelve inequivalent Si+1.33- sites. In the first Si+1.33- site, Si+1.33- is bonded in a 5-coordinate geometry to three Mg2+ and two Si+1.33- atoms. There are one shorter (2.33 Å) and one longer (2.42 Å) Si–Si bond lengths. In the second 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 (2.49 Å) and one longer (2.50 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. Both Si–Si bond lengths are 2.39 Å. In the fourth Si+1.33- site, Si+1.33- is bonded in a 8-coordinate geometry to four Mg2+ and four Si+1.33- atoms. There are one shorter (2.56 Å) and one longer (2.58 Å) Si–Si bond lengths. 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 2.51–2.60 Å. In the sixth 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 2.44–2.54 Å. 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 2.46–2.49 Å. In the eighth 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 (2.50 Å) and one longer (2.52 Å) Si–Si bond lengths. In the ninth Si+1.33- site, Si+1.33- is bonded in a 8-coordinate geometry to four Mg2+ and four Si+1.33- atoms. In the tenth Si+1.33- site, Si+1.33- is bonded in a 8-coordinate geometry to four Mg2+ and four Si+1.33- atoms. In the eleventh 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 twelfth Si+1.33- site, Si+1.33- is bonded in a 9-coordinate geometry to six Mg2+ and three Si+1.33- atoms.

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 to four Si atoms to form a mixture of distorted corner and edge-sharing MgSi4 tetrahedra. There are a spread of Mg–Si bond distances ranging from 2.68–2.83 Å. In the second Mg site, Mg is bonded in a 5-coordinate geometry to six Si atoms. There are a spread of Mg–Si bond distances ranging from 2.77–3.23 Å. In the third Mg site, Mg is bonded to four Si atoms to form a mixture of distorted corner and edge-sharing MgSi4 tetrahedra. There are a spread of Mg–Si bond distances ranging from 2.71–2.80 Å. In the fourth 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 2.73–2.90 Å. In the fifth Mg site, Mg is bonded to four Si atoms to form a mixture of distorted corner and edge-sharing MgSi4 tetrahedra. There are a spread of Mg–Si bond distances ranging from 2.70–2.78 Å. In the sixth Mg site, Mg is bonded to four Si atoms to form a mixture of distorted corner and edge-sharing MgSi4 tetrahedra. There are a spread of Mg–Si bond distances ranging from 2.80–2.85 Å. In the seventh Mg site, Mg is bonded in a distorted single-bond geometry to two Si atoms. There are one shorter (2.73 Å) and one longer (3.11 Å) Mg–Si bond lengths. In the eighth Mg site, Mg is bonded in a distorted trigonal non-coplanar geometry to three Si atoms. There are a spread of Mg–Si bond distances ranging from 2.68–2.78 Å. In the ninth Mg site, Mg is bonded in a distorted trigonal non-coplanar geometry to three Si atoms. There are a spread of Mg–Si bond distances ranging from 2.69–2.74 Å. In the tenth Mg site, Mg is bonded in a distorted trigonal non-coplanar geometry to three Si atoms. There are a spread of Mg–Si bond distances ranging from 2.71–2.88 Å. In the eleventh Mg site, Mg is bonded in a 3-coordinate geometry to three Si atoms. There are a spread of Mg–Si bond distances ranging from 2.72–2.88 Å. In the twelfth Mg site, Mg is bonded to four Si atoms to form distorted corner-sharing MgSi4 trigonal pyramids. There are a spread of Mg–Si bond distances ranging from 2.71–2.83 Å. In the thirteenth 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 2.74–2.80 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 2.73–2.88 Å. In the fifteenth 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 2.68–2.83 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 2.71–2.94 Å. In the seventeenth Mg site, Mg is bonded in a distorted trigonal non-coplanar geometry to three Si atoms. There are a spread of Mg–Si bond distances ranging from 2.66–2.78 Å. In the eighteenth 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 2.77–2.91 Å. There are ten inequivalent Si sites. In the first Si site, Si is bonded in a 8-coordinate geometry to six Mg and two Si atoms. There are one shorter (2.39 Å) and one longer (2.45 Å) Si–Si bond lengths. In the second Si site, Si is bonded in a 7-coordinate geometry to six Mg and one Si atom. In the third Si site, Si is bonded in a 3-coordinate geometry to seven Mg and one Si atom. The Si–Si bond length is 2.61 Å. In the fourth Si site, Si is bonded in a 8-coordinate geometry to six Mg and one Si atom. In the fifth Si site, Si is bonded in a 8-coordinate geometry to six Mg and two Si atoms. The Si–Si bond length is 2.40 Å. 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 6-coordinate geometry to five Mg and one Si atom. 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 nine Mg atoms. In the tenth Si site, Si is bonded in a 8-coordinate geometry to eight Mg 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 9-coordinate geometry to nine Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.74–3.04 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 2.82–3.00 Å. In the third 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 2.77–3.00 Å. In the fourth 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 2.80–3.00 Å. In the fifth Mg2+ site, Mg2+ is bonded in a 7-coordinate geometry to eight Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.80–3.14 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 2.85–3.06 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 2.67–2.96 Å. In the eighth 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 2.78–2.91 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 six Mg2+ and three Si+1.33- atoms. There are a spread of Si–Si bond distances ranging from 2.38–2.64 Å. In the second Si+1.33- site, Si+1.33- is bonded in a 9-coordinate geometry to six Mg2+ and three Si+1.33- atoms. Both Si–Si bond lengths are 2.54 Å. In the third Si+1.33- site, Si+1.33- is bonded in a distorted q6 geometry to five Mg2+ and four Si+1.33- atoms. Both Si–Si bond lengths are 2.48 Å. In the fourth Si+1.33- site, Si+1.33- is bonded in a 8-coordinate geometry to four Mg2+ and four Si+1.33- atoms. Both Si–Si bond lengths are 2.53 Å. In the fifth 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 2.41–2.54 Å. In the sixth 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 one shorter (2.41 Å) and two longer (2.50 Å) Si–Si bond lengths. In the seventh 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 one shorter (2.48 Å) and two longer (2.51 Å) Si–Si bond lengths. In the eighth 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 ninth Si+1.33- site, Si+1.33- is bonded in a 7-coordinate geometry to three Mg2+ and four Si+1.33- atoms. In the tenth 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 2.41 Å. In the eleventh 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 twelfth Si+1.33- site, Si+1.33- is bonded in a 9-coordinate geometry to six Mg2+ and three Si+1.33- 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 2.73–3.08 Å. In the second 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 2.80–3.01 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 2.74–3.08 Å. In the fourth 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 2.70–3.18 Å. In the fifth 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 2.68–3.01 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 2.75–3.14 Å. In the seventh 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 2.74–3.10 Å. In the eighth 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 2.71–3.10 Å. There are twelve inequivalent Si+1.33- sites. In the first 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 2.41–2.49 Å. In the second Si+1.33- site, Si+1.33- is bonded to five Mg2+ and three Si+1.33- atoms to form a mixture of distorted edge and corner-sharing SiMg5Si3 hexagonal bipyramids. There are one shorter (2.42 Å) and one longer (2.46 Å) Si–Si bond lengths. 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 2.46 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 2.44 Å. In the fifth 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 2.36–2.48 Å. 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 (2.46 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 7-coordinate geometry to four Mg2+ and three Si+1.33- atoms. There are one shorter (2.41 Å) and one longer (2.45 Å) Si–Si bond lengths. In the eighth Si+1.33- site, Si+1.33- is bonded in a 8-coordinate geometry to five Mg2+ and three Si+1.33- atoms. Both Si–Si bond lengths are 2.44 Å. In the ninth 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 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 7-coordinate geometry to six Mg2+ and one Si+1.33- atom.

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 5-coordinate geometry to five Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.87–3.01 Å. In the second Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to seven Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.65–3.19 Å. In the third Mg2+ site, Mg2+ is bonded to four Si+1.33- atoms to form distorted corner-sharing MgSi4 tetrahedra. There are a spread of Mg–Si bond distances ranging from 2.73–2.92 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 2.62–2.93 Å. In the fifth Mg2+ site, Mg2+ is bonded in a 4-coordinate geometry to five Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.70–3.21 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 2.72–2.98 Å. In the seventh 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 2.72–3.25 Å. In the eighth 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 2.71–3.23 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 four Mg2+ and two Si+1.33- atoms. There are one shorter (2.48 Å) and one longer (2.59 Å) Si–Si bond lengths. In the second Si+1.33- site, Si+1.33- is bonded in a 1-coordinate geometry to four Mg2+ and three Si+1.33- atoms. There are one shorter (2.39 Å) and one longer (2.56 Å) Si–Si bond lengths. In the third 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 (2.53 Å) and one longer (2.56 Å) Si–Si bond lengths. 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 2.47 Å. In the fifth 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 2.49–2.62 Å. In the sixth Si+1.33- site, Si+1.33- is bonded in a 1-coordinate geometry to two Mg2+ and five Si+1.33- atoms. There are a spread of Si–Si bond distances ranging from 2.53–2.58 Å. In the seventh Si+1.33- site, Si+1.33- is bonded in a 2-coordinate geometry to four Mg2+ and five Si+1.33- atoms. There are a spread of Si–Si bond distances ranging from 2.40–2.67 Å. In the eighth Si+1.33- site, Si+1.33- is bonded in a 10-coordinate geometry to four Mg2+ and six Si+1.33- atoms. There are a spread of Si–Si bond distances ranging from 2.47–2.57 Å. In the ninth 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 tenth Si+1.33- site, Si+1.33- is bonded in a 2-coordinate geometry to three 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 four Mg2+ and three Si+1.33- atoms. In the twelfth Si+1.33- site, Si+1.33- is bonded in a 7-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 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 2-coordinate geometry to four Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.86–3.13 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 2.60–2.79 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 2.77–3.13 Å. In the fourth 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 2.79–3.06 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 2.94–3.13 Å. In the sixth Mg2+ site, Mg2+ is bonded in a single-bond geometry to one Si+2.40- atom. The Mg–Si bond length is 2.68 Å. In the seventh Mg2+ site, Mg2+ is bonded in a 7-coordinate geometry to eight Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.79–3.26 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 2.88–3.07 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 2.87 Å. In the tenth 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 2.96–3.15 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 2.77 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 2.79–3.16 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 (2.37 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 2.43 Å. In the third Si+2.40- site, Si+2.40- is bonded in a 12-coordinate geometry to five Mg2+ and five Si+2.40- atoms. There are a spread of Si–Si bond distances ranging from 2.56–2.80 Å. 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 2.46–2.73 Å. In the fifth 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 2.46–2.61 Å. In the sixth 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 seventh Si+2.40- site, Si+2.40- is bonded in a 1-coordinate geometry to six Mg2+ and four Si+2.40- atoms. There are one shorter (2.53 Å) and one longer (2.55 Å) Si–Si bond lengths. 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 8-coordinate geometry to four 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 8-coordinate geometry to eight Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.72–3.10 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 2.63–2.89 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 2.78–3.00 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 2.75–3.12 Å. In the fifth Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to nine Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.79–3.25 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 2.78–3.11 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 2.70–3.10 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 2.81–3.15 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 a spread of Si–Si bond distances ranging from 2.47–2.51 Å. In the second 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 (2.50 Å) and one longer (2.51 Å) Si–Si bond lengths. In the third Si+1.33- site, Si+1.33- is bonded in a 8-coordinate geometry to four Mg2+ and four Si+1.33- atoms. There are one shorter (2.53 Å) and one longer (2.54 Å) Si–Si bond lengths. In the fourth Si+1.33- site, Si+1.33- is bonded in a 8-coordinate geometry to four Mg2+ and four Si+1.33- atoms. There are one shorter (2.50 Å) and one longer (2.54 Å) Si–Si bond lengths. In the fifth Si+1.33- site, Si+1.33- is bonded in a 6-coordinate geometry to two equivalent Mg2+ and four Si+1.33- atoms. There are a spread of Si–Si bond distances ranging from 2.37–2.55 Å. In the sixth 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 one shorter (2.49 Å) and two longer (2.53 Å) Si–Si bond lengths. In the seventh Si+1.33- site, Si+1.33- is bonded in a 6-coordinate geometry to six Mg2+ and two Si+1.33- atoms. The Si–Si bond length is 2.57 Å. In the eighth 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 (2.44 Å) and one longer (2.48 Å) Si–Si bond lengths. In the ninth Si+1.33- site, Si+1.33- is bonded in a 7-coordinate geometry to five Mg2+ and two equivalent Si+1.33- atoms. In the tenth Si+1.33- site, Si+1.33- is bonded in a 8-coordinate geometry to four Mg2+ and four Si+1.33- atoms. In the eleventh 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 twelfth Si+1.33- site, Si+1.33- is bonded in a 9-coordinate geometry to six Mg2+ and three Si+1.33- 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 2.69–3.07 Å. In the second 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 2.74–3.02 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 2.74–2.96 Å. In the fourth Mg2+ site, Mg2+ is bonded to five Si+1.33- atoms to form distorted edge-sharing MgSi5 square pyramids. There are a spread of Mg–Si bond distances ranging from 2.75–2.91 Å. In the fifth 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 2.79–2.84 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 2.70–3.06 Å. In the seventh 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 2.80–3.17 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 2.65–3.10 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 a spread of Si–Si bond distances ranging from 2.44–2.49 Å. In the second Si+1.33- site, Si+1.33- is bonded in a 5-coordinate geometry to two equivalent Mg2+ and three Si+1.33- atoms. Both Si–Si bond lengths are 2.37 Å. In the third Si+1.33- site, Si+1.33- is bonded in a 8-coordinate geometry to four Mg2+ and four Si+1.33- atoms. There are one shorter (2.56 Å) and one longer (2.57 Å) Si–Si bond lengths. 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 2.39 Å. In the fifth Si+1.33- site, Si+1.33- is bonded in a 5-coordinate geometry to two equivalent Mg2+ and three Si+1.33- atoms. There are one shorter (2.34 Å) and two longer (2.40 Å) Si–Si bond lengths. In the sixth 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 2.45–2.53 Å. In the seventh Si+1.33- site, Si+1.33- is bonded in a 6-coordinate geometry to four Mg2+ and two Si+1.33- atoms. The Si–Si bond length is 2.35 Å. In the eighth Si+1.33- site, Si+1.33- is bonded in a 1-coordinate geometry to four Mg2+ and three Si+1.33- atoms. There are one shorter (2.50 Å) and one longer (2.54 Å) Si–Si bond lengths. In the ninth Si+1.33- site, Si+1.33- is bonded in a 7-coordinate geometry to five Mg2+ and two equivalent Si+1.33- atoms. In the tenth Si+1.33- site, Si+1.33- is bonded in a 8-coordinate geometry to four Mg2+ and four Si+1.33- atoms. In the eleventh 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 twelfth Si+1.33- site, Si+1.33- is bonded in a 7-coordinate geometry to six Mg2+ and one Si+1.33- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg6Si5 by Materials Project

Mg6Si5 crystallizes in the monoclinic Pm 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 2.79 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 2.67–2.85 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 2.86–3.12 Å. In the fourth 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 2.79–2.90 Å. In the fifth 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 2.88–3.09 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 2.92–3.13 Å. In the seventh Mg2+ site, Mg2+ is bonded in a 8-coordinate geometry to eight Si+2.40- atoms. There are four shorter (2.93 Å) and four longer (2.97 Å) Mg–Si bond lengths. In the eighth 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 2.75–3.11 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 2.60 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 2.79–3.15 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 2.83 Å. In the twelfth Mg2+ site, Mg2+ is bonded in a distorted T-shaped geometry to three Si+2.40- atoms. There are two shorter (2.89 Å) and one longer (3.03 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 9-coordinate geometry to seven Mg2+ and two Si+2.40- atoms. There are one shorter (2.39 Å) and one longer (2.48 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 9-coordinate geometry to six Mg2+ and three Si+2.40- atoms. There are two shorter (2.45 Å) and one longer (2.78 Å) Si–Si bond lengths. In the fourth Si+2.40- site, Si+2.40- is bonded in a 1-coordinate geometry to five Mg2+ and four Si+2.40- atoms. There are a spread of Si–Si bond distances ranging from 2.38–2.76 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 2.56 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 one shorter (2.51 Å) and two longer (2.53 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 five Mg2+ and five Si+2.40- atoms. Both Si–Si bond lengths are 2.62 Å. In the ninth Si+2.40- site, Si+2.40- is bonded in a 8-coordinate geometry to four 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↗
DOE OSTI2020

Materials Data on Ca8Al11Fe(Si3O13)4 by Materials Project

Ca8FeAl11(Si3O13)4 is Esseneite-derived structured and 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 ten O atoms. There are a spread of Ca–O bond distances ranging from 2.28–3.02 Å. In the second 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 2.26–2.72 Å. In the third 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 2.28–2.72 Å. In the fourth 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 2.28–2.73 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 2.33–2.53 Å. In the sixth Ca site, Ca is bonded in a 9-coordinate geometry to six O atoms. There are a spread of Ca–O bond distances ranging from 2.32–2.53 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 2.32–2.53 Å. In the eighth Ca site, Ca is bonded in a 9-coordinate geometry to six O atoms. There are a spread of Ca–O bond distances ranging from 2.31–2.52 Å. Fe is bonded to six O atoms to form distorted 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 1.92–2.30 Å. There are seven 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 four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.85–1.97 Å. In the second 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 1.84–1.99 Å. In the third 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 1.85–1.98 Å. In the fourth Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with four SiO4 tetrahedra and edges with two equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.85–1.98 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 1.81–2.32 Å. In the sixth 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 1.80–2.33 Å. In the seventh 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 1.81–2.32 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 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 is one shorter (1.59 Å) and three longer (1.66 Å) Si–O bond length. In the second 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 54–56°. There is one shorter (1.59 Å) and three longer (1.66 Å) Si–O bond length. In the third 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 54–56°. There is one shorter (1.59 Å) and three longer (1.66 Å) Si–O bond length. In the fourth 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 53–57°. There is one shorter (1.60 Å) and three longer (1.66 Å) Si–O bond length. In the fifth 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 47–55°. There are a spread of Si–O bond distances ranging from 1.64–1.68 Å. In the sixth 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 47–53°. There are a spread of Si–O bond distances ranging from 1.65–1.67 Å. In the seventh 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 47–53°. There are a spread of Si–O bond distances ranging from 1.65–1.68 Å. In the eighth 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 47–53°. There are a spread of Si–O bond distances ranging from 1.65–1.67 Å. In the ninth 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 36–53°. There is one shorter (1.60 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 corners with three AlO6 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 27–52°. There are a spread of Si–O bond distances ranging from 1.60–1.65 Å. In the eleventh 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 26–52°. There is one shorter (1.60 Å) and three longer (1.64 Å) Si–O bond length. In the twelfth 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 27–52°. There is one shorter (1.60 Å) and three longer (1.65 Å) Si–O bond length. There are forty inequivalent O sites. In the first O site, O is bonded in a distorted bent 150 degrees geometry to two equivalent Ca, one Fe, and one Si atom. In the second O site, O is bonded in a bent 150 degrees geometry to one Al and one Si atom. In the third O site, O is bonded in a bent 150 degrees geometry to one Al and one Si atom. In the fourth O site, O is bonded in a bent 150 degrees geometry to one Al and one Si atom. In the fifth O site, O is bonded in a trigonal non-coplanar geometry to one Fe and two equivalent Al atoms. In the sixth O site, O is bonded in a trigonal non-coplanar geometry to three Al atoms. In the seventh O site, O is bonded in a trigonal non-coplanar geometry to three Al atoms. In the eighth O site, O is bonded in a trigonal non-coplanar geometry to three Al atoms. In the ninth 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 tenth 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 eleventh 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 twelfth O site, O is bonded to one Ca, two Al, and one Si atom to form distorted OCaAl2Si tetrahedra that share corners with two OCaAlFeSi tetrahedra and an edgeedge with one OCaAl2Si tetrahedra. In the thirteenth O site, O is bonded in a 2-coordinate geometry to two Ca, one Al, and one Si atom. In the fourteenth O site, O is bonded in a 2-coordinate geometry to two Ca, one Al, and one Si atom. In the fifteenth O site, O is bonded in a 2-coordinate geometry to two Ca, one Al, and one Si atom. In the sixteenth O site, O is bonded in a 4-coordinate geometry to two Ca, one Al, and one Si atom. In the seventeenth O site, O is bonded in a 3-coordinate geometry to two equivalent Al and one Si atom. In the eighteenth O site, O is bonded in a 3-coordinate geometry to two equivalent Al and one Si atom. In the nineteenth O site, O is bonded in a 3-coordinate geometry to two equivalent Al and one Si atom. In the twentieth O site, O is bonded in a 4-coordinate geometry to two equivalent Al 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 distorted rectangular see-saw-like geometry to one Ca, two equivalent Al, and one Si atom. In the twenty-sixth O site, O is bonded in a 4-coordinate geometry to one Ca, two equivalent Al, and one Si atom. In the twenty-seventh O site, O is bonded in a 4-coordinate geometry to one Ca, two equivalent Al, and one Si atom. In the twenty-eighth O site, O is bonded in a 4-coordinate geometry to one Ca, two equivalent Al, and one Si atom. In the twenty-ninth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the thirtieth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the thirty-first O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the thirty-second O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the thirty-third O site, O is bonded in a distorted trigonal non-coplanar geometry to one Ca and two equivalent Al atoms. In the thirty-fourth O site, O is bonded in a distorted trigonal non-coplanar geometry to one Ca and two equivalent Al atoms. In the thirty-fifth O site, O is bonded in a distorted trigonal non-coplanar geometry to one Ca and two equivalent Al atoms. In the thirty-sixth O site, O is bonded in a distorted trigonal non-coplanar geometry to one Ca and two equivalent Al atoms. In the thirty-seventh O site, O is bonded in a 4-coordinate geometry to two Ca, one Fe, and one Si atom. In the thirty-eighth O site, O is bonded in a 2-coordinate geometry to two Ca, one Al, and one Si atom. In the thirty-ninth O site, O is bonded in a 2-coordinate geometry to two Ca, one Al, and one Si atom. In the fortieth O site, O is bonded in a 2-coordinate geometry to two Ca, one Al, and one Si atom.

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 to five Si+1.33- atoms to form distorted corner-sharing MgSi5 trigonal bipyramids. There are a spread of Mg–Si bond distances ranging from 2.73–2.92 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 2.76–3.10 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 2.73–3.06 Å. In the fourth 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 2.70–3.15 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 2.75–3.06 Å. In the sixth Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to seven Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.66–3.21 Å. In the seventh 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 2.73–3.15 Å. In the eighth 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 2.71–3.08 Å. There are twelve inequivalent Si+1.33- sites. In the first Si+1.33- site, Si+1.33- is bonded in a 8-coordinate geometry to four Mg2+ and four Si+1.33- atoms. There are a spread of Si–Si bond distances ranging from 2.45–2.63 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 one shorter (2.44 Å) and one longer (2.51 Å) Si–Si bond lengths. 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 2.38 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 2.46 Å. 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 (2.42 Å) and one longer (2.54 Å) Si–Si bond lengths. In the sixth Si+1.33- site, Si+1.33- is bonded in a 8-coordinate geometry to four Mg2+ and four Si+1.33- atoms. There are a spread of Si–Si bond distances ranging from 2.40–2.66 Å. In the seventh Si+1.33- site, Si+1.33- is bonded to five Mg2+ and three Si+1.33- atoms to form a mixture of distorted corner and edge-sharing SiMg5Si3 hexagonal bipyramids. There are a spread of Si–Si bond distances ranging from 2.41–2.49 Å. In the eighth Si+1.33- site, Si+1.33- is bonded in a 8-coordinate geometry to four Mg2+ and four Si+1.33- atoms. The Si–Si bond length is 2.41 Å. In the ninth 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 tenth 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 eleventh Si+1.33- site, Si+1.33- is bonded in a 4-coordinate geometry to five Mg2+ and three 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 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 9-coordinate geometry to nine Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.72–3.05 Å. In the second Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to eight Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.78–3.20 Å. In the third 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 2.77–3.01 Å. In the fourth 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 2.79–2.99 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 2.72–3.04 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 2.84–3.07 Å. In the seventh Mg2+ site, Mg2+ is bonded in a 7-coordinate geometry to eight Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.73–3.26 Å. In the eighth 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 2.72–2.93 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 six Mg2+ and three Si+1.33- atoms. There are a spread of Si–Si bond distances ranging from 2.41–2.65 Å. In the second 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 one shorter (2.50 Å) and one longer (2.56 Å) Si–Si bond lengths. In the third Si+1.33- site, Si+1.33- is bonded in a distorted q6 geometry to five Mg2+ and four Si+1.33- atoms. There are one shorter (2.48 Å) and one longer (2.50 Å) Si–Si bond lengths. In the fourth Si+1.33- site, Si+1.33- is bonded in a distorted q6 geometry to five Mg2+ and four Si+1.33- atoms. There are one shorter (2.54 Å) and one longer (2.58 Å) Si–Si bond lengths. In the fifth Si+1.33- site, Si+1.33- is bonded in a 11-coordinate geometry to seven Mg2+ and four Si+1.33- atoms. There are a spread of Si–Si bond distances ranging from 2.53–2.79 Å. In the sixth 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 one shorter (2.43 Å) and two longer (2.49 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 2.40–2.49 Å. In the eighth 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 ninth Si+1.33- site, Si+1.33- is bonded in a 2-coordinate geometry to three Mg2+ and four Si+1.33- atoms. In the tenth 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 2.43 Å. In the eleventh 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 twelfth Si+1.33- site, Si+1.33- is bonded in a 9-coordinate geometry to six Mg2+ and three Si+1.33- 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 8-coordinate geometry to eight Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.75–3.04 Å. In the second 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 2.60–2.91 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 2.72–3.09 Å. In the fourth 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 2.81–3.09 Å. In the fifth Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to seven Si+1.33- atoms. There are a spread of Mg–Si bond distances ranging from 2.72–3.23 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 2.72–3.07 Å. In the seventh 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 2.64–3.16 Å. In the eighth 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 2.78–3.09 Å. There are twelve inequivalent Si+1.33- sites. In the first 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 2.44–2.49 Å. In the second Si+1.33- site, Si+1.33- is bonded to five Mg2+ and three Si+1.33- atoms to form a mixture of distorted edge and corner-sharing SiMg5Si3 hexagonal bipyramids. There are one shorter (2.43 Å) and one longer (2.44 Å) Si–Si bond lengths. 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 2.45 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 2.42 Å. In the fifth Si+1.33- site, Si+1.33- is bonded in a 8-coordinate geometry to four Mg2+ and four Si+1.33- atoms. There are a spread of Si–Si bond distances ranging from 2.37–2.53 Å. 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 (2.43 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 7-coordinate geometry to five Mg2+ and two Si+1.33- atoms. The Si–Si bond length is 2.51 Å. In the eighth Si+1.33- site, Si+1.33- is bonded to five Mg2+ and three Si+1.33- atoms to form a mixture of distorted edge and corner-sharing SiMg5Si3 hexagonal bipyramids. There are one shorter (2.42 Å) and one longer (2.44 Å) Si–Si bond lengths. In the ninth 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 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 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 T-shaped geometry to three Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.85–3.18 Å. In the second 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 2.79–3.07 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 2.66–2.97 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 2.77–3.18 Å. In the fifth Mg2+ site, Mg2+ is bonded to five Si+2.40- atoms to form distorted MgSi5 trigonal bipyramids that share corners with two equivalent MgSi5 trigonal bipyramids, corners with two equivalent MgSi4 trigonal pyramids, and an edgeedge with one MgSi4 trigonal pyramid. There are a spread of Mg–Si bond distances ranging from 2.77–3.06 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 2.72–3.14 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 2.73–3.07 Å. In the eighth Mg2+ site, Mg2+ is bonded in a distorted rectangular see-saw-like geometry to four Si+2.40- atoms. There are a spread of Mg–Si bond distances ranging from 2.71–3.09 Å. In the ninth 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 2.82–3.07 Å. In the tenth 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 2.72–2.93 Å. In the eleventh 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 2.83–2.98 Å. In the twelfth Mg2+ site, Mg2+ is bonded to four Si+2.40- atoms to form a mixture of distorted corner and edge-sharing MgSi4 trigonal pyramids. There are a spread of Mg–Si bond distances ranging from 2.80–2.89 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 six Mg2+ and two Si+2.40- atoms. There are one shorter (2.38 Å) and one longer (2.45 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 (2.43 Å) and one longer (2.47 Å) Si–Si bond lengths. In the third 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 (2.36 Å) and one longer (2.53 Å) Si–Si bond lengths. 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. Both Si–Si bond lengths are 2.40 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 (2.43 Å) and one longer (2.49 Å) Si–Si bond lengths. 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 2.37 Å. In the seventh Si+2.40- site, Si+2.40- is bonded in a 7-coordinate geometry to four Mg2+ and three Si+2.40- atoms. The Si–Si bond length is 2.44 Å. 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 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 9-coordinate geometry to seven Mg2+ and two Si+2.40- atoms.

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 to one Mg and four Si atoms to form distorted MgMgSi4 tetrahedra that share a cornercorner with one SiMg8 hexagonal bipyramid, corners with two equivalent MgMgSi4 tetrahedra, and edges with two MgMgSi4 tetrahedra. The Mg–Mg bond length is 3.15 Å. There are a spread of Mg–Si bond distances ranging from 2.77–2.86 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 3.04 Å. There are a spread of Mg–Si bond distances ranging from 2.73–2.94 Å. In the third Mg site, Mg is bonded in a 3-coordinate geometry to three Si atoms. There are a spread of Mg–Si bond distances ranging from 2.62–2.79 Å. In the fourth 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 2.69–2.82 Å. In the fifth Mg site, Mg is bonded to one Mg and four Si atoms to form distorted MgMgSi4 tetrahedra that share a cornercorner with one SiMg8 hexagonal bipyramid, corners with three MgMgSi4 tetrahedra, and edges with two MgMgSi4 tetrahedra. The Mg–Mg bond length is 2.96 Å. There are a spread of Mg–Si bond distances ranging from 2.72–2.93 Å. In the sixth Mg site, Mg is bonded to four Si atoms to form a mixture of distorted corner and edge-sharing MgSi4 tetrahedra. There are a spread of Mg–Si bond distances ranging from 2.71–2.79 Å. In the seventh Mg site, Mg is bonded in a distorted T-shaped geometry to three Si atoms. There are a spread of Mg–Si bond distances ranging from 2.76–2.82 Å. In the eighth 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 2.67–2.94 Å. In the ninth Mg site, Mg is bonded in a 3-coordinate geometry to three Si atoms. There are a spread of Mg–Si bond distances ranging from 2.79–2.93 Å. In the tenth Mg site, Mg is bonded in a 3-coordinate geometry to one Mg and three Si atoms. The Mg–Mg bond length is 3.03 Å. There are a spread of Mg–Si bond distances ranging from 2.70–2.84 Å. In the eleventh Mg site, Mg is bonded in a 3-coordinate geometry to three Si atoms. There are two shorter (2.78 Å) and one longer (2.87 Å) Mg–Si bond lengths. In the twelfth Mg site, Mg is bonded in a 3-coordinate geometry to three Si atoms. There are a spread of Mg–Si bond distances ranging from 2.67–2.83 Å. In the thirteenth 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 2.78–2.87 Å. In the fourteenth Mg site, Mg is bonded in a 3-coordinate geometry to five Mg and five Si atoms. The Mg–Mg bond length is 3.16 Å. There are a spread of Mg–Si bond distances ranging from 2.66–3.05 Å. In the fifteenth Mg site, Mg is bonded in a 3-coordinate geometry to three Si atoms. There are a spread of Mg–Si bond distances ranging from 2.69–2.89 Å. In the sixteenth Mg site, Mg is bonded in a 3-coordinate geometry to one Mg and four Si atoms. There are a spread of Mg–Si bond distances ranging from 2.76–3.14 Å. In the seventeenth Mg site, Mg is bonded in a distorted trigonal non-coplanar geometry to three Si atoms. There are a spread of Mg–Si bond distances ranging from 2.76–2.83 Å. In the eighteenth 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 2.64–2.87 Å. There are ten inequivalent Si sites. In the first Si site, Si is bonded in a 8-coordinate geometry to seven Mg and one Si atom. The Si–Si bond length is 2.43 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 6-coordinate geometry to four Mg and two Si atoms. There are one shorter (2.41 Å) and one longer (2.45 Å) Si–Si bond lengths. In the fourth Si site, Si is bonded in a 8-coordinate geometry to six Mg and two Si atoms. The Si–Si bond length is 2.54 Å. In the fifth Si site, Si is bonded in a 7-coordinate geometry to seven Mg atoms. In the sixth Si site, Si is bonded in a 8-coordinate geometry to seven Mg and one Si atom. In the seventh Si site, Si is bonded in a 7-coordinate geometry to six Mg and one Si atom. In the eighth Si site, Si is bonded in a 8-coordinate geometry to seven Mg and one Si atom. In the ninth Si site, Si is bonded to eight Mg atoms to form distorted SiMg8 hexagonal bipyramids that share corners with two equivalent SiMg8 hexagonal bipyramids, corners with two MgMgSi4 tetrahedra, and an edgeedge with one SiMg8 hexagonal bipyramid. In the tenth Si site, Si is bonded to eight Mg atoms to form a mixture of distorted corner and edge-sharing SiMg8 hexagonal bipyramids.

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 2.88 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 2.69–2.92 Å. In the third 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 2.85–3.14 Å. In the fourth 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 2.74–2.94 Å. In the fifth 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 2.85–3.07 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 2.91–3.17 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 2.90–3.01 Å. In the eighth 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 2.76–3.18 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 (2.91 Å) and one longer (3.01 Å) Mg–Si bond lengths. 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 2.75–3.11 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 2.84 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 2.58 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 (2.38 Å) and one longer (2.63 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 2.42 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 2.45–2.85 Å. 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 2.57–2.65 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 (2.37 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 seven Mg2+ and three Si+2.40- atoms. There are two shorter (2.50 Å) and one longer (2.51 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 five Mg2+ and five Si+2.40- atoms. The Si–Si bond length is 2.67 Å. In the ninth Si+2.40- site, Si+2.40- is bonded in a 1-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↗
DOE OSTI2020

Materials Data on K8Nd3(Si4O11)3 by Materials Project

K8Nd3(Si4O11)3 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eight inequivalent K sites. In the first K site, K is bonded in a 6-coordinate geometry to six O atoms. There are a spread of K–O bond distances ranging from 2.81–2.97 Å. In the second K site, K is bonded in a 6-coordinate geometry to six O atoms. There are a spread of K–O bond distances ranging from 2.79–2.99 Å. In the third K site, K is bonded in a 5-coordinate geometry to five O atoms. There are a spread of K–O bond distances ranging from 2.65–2.96 Å. In the fourth K site, K is bonded in a 4-coordinate geometry to four O atoms. There are a spread of K–O bond distances ranging from 2.71–2.86 Å. In the fifth K site, K is bonded in a 6-coordinate geometry to six O atoms. There are a spread of K–O bond distances ranging from 2.75–3.21 Å. In the sixth K site, K is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of K–O bond distances ranging from 2.59–3.30 Å. In the seventh K site, K is bonded in a distorted rectangular see-saw-like geometry to four O atoms. There are a spread of K–O bond distances ranging from 2.70–2.89 Å. In the eighth K site, K is bonded in a 5-coordinate geometry to five O atoms. There are a spread of K–O bond distances ranging from 2.62–3.02 Å. There are three inequivalent Nd sites. In the first Nd site, Nd is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Nd–O bond distances ranging from 2.32–2.48 Å. In the second Nd site, Nd is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Nd–O bond distances ranging from 2.34–2.49 Å. In the third Nd site, Nd is bonded to six O atoms to form NdO6 octahedra that share corners with six SiO4 tetrahedra. There are a spread of Nd–O bond distances ranging from 2.34–2.39 Å. There are twelve inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.67 Å. In the second Si site, Si is bonded to four O atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.67 Å. In the third Si site, Si is bonded to four O atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.68 Å. In the fourth Si site, Si is bonded to four O atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.62–1.69 Å. In the fifth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one NdO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 37°. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the sixth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one NdO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 40°. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the seventh Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one NdO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 47°. There is one shorter (1.60 Å) and three longer (1.65 Å) Si–O bond length. In the eighth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one NdO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 49°. 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 a cornercorner with one NdO6 octahedra and corners with two SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 33°. There are a spread of Si–O bond distances ranging from 1.61–1.69 Å. In the tenth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one NdO6 octahedra and corners with two SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 34°. There are a spread of Si–O bond distances ranging from 1.61–1.69 Å. In the eleventh Si site, Si is bonded to four O atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.62–1.65 Å. In the twelfth Si site, Si is bonded to four O atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. There are thirty-three inequivalent O sites. In the first O site, O is bonded in a distorted bent 150 degrees geometry to one K and two Si atoms. In the second O site, O is bonded in a distorted bent 150 degrees geometry to one K and two Si atoms. In the third O site, O is bonded in a 1-coordinate geometry to two K, one Nd, and one Si atom. In the fourth O site, O is bonded in a 1-coordinate geometry to two K, one Nd, and one Si atom. In the fifth O site, O is bonded in a 1-coordinate geometry to two K, one Nd, and one Si atom. In the sixth O site, O is bonded in a 1-coordinate geometry to two K, one Nd, and one Si atom. In the seventh O site, O is bonded in a 4-coordinate geometry to two K, one Nd, and one Si atom. In the eighth O site, O is bonded in a 4-coordinate geometry to two K, one Nd, and one Si atom. In the ninth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the tenth O site, O is bonded in a distorted bent 150 degrees geometry to two Si atoms. In the eleventh O site, O is bonded in a distorted bent 150 degrees geometry to one K and two Si atoms. In the twelfth O site, O is bonded in a distorted bent 150 degrees geometry to one K and two Si atoms. In the thirteenth O site, O is bonded in a 2-coordinate geometry to one K and two Si atoms. In the fourteenth O site, O is bonded in a 2-coordinate geometry to one K and two Si atoms. In the fifteenth O site, O is bonded in a 4-coordinate geometry to two K, one Nd, and one Si atom. In the sixteenth O site, O is bonded in a 4-coordinate geometry to two K, one Nd, 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 4-coordinate geometry to two K, one Nd, and one Si atom. In the twentieth O site, O is bonded in a distorted rectangular see-saw-like geometry to two K, one Nd, and one Si atom. In the twenty-first O site, O is bonded in a distorted bent 150 degrees geometry to one K and two Si atoms. In the twenty-second O site, O is bonded in a distorted bent 150 degrees geometry to one K and two Si atoms. In the twenty-third O site, O is bonded in a distorted bent 120 degrees geometry to two K and two Si atoms. In the twenty-fourth O site, O is bonded in a distorted bent 120 degrees geometry to two K and two Si atoms. In the twenty-fifth O site, O is bonded in a 1-coordinate geometry to two Nd and one Si atom. In the twenty-sixth O site, O is bonded in a 3-coordinate geometry to two Nd and one Si atom. In the twenty-seventh O site, O is bonded in a 4-coordinate geometry to two K, one Nd, and one Si atom. In the twenty-eighth O site, O is bonded in a distorted rectangular see-saw-like geometry to two K, one Nd, and one Si atom. In the twenty-ninth O site, O is bonded in a linear geometry to two Si atoms. In the thirtieth O site, O is bonded in a linear geometry to one K and two Si atoms. In the thirty-first O site, O is bonded in a 4-coordinate geometry to two K, one Nd, and one Si atom. In the thirty-second O site, O is bonded in a 4-coordinate geometry to two K, one Nd, and one Si atom. In the thirty-third O site, O is bonded in a T-shaped geometry to three K atoms.

36 MATERIALS SCIENCE↗