Materials Data on Ca3Mg5(SiO3)8 by Materials Project
Ca3Mg5(SiO3)8 is Esseneite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are three inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.33–2.85 Å. In the second Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.30–2.77 Å. In the third Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.33–2.82 Å. There are five inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six SiO4 tetrahedra and edges with two equivalent MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.06–2.17 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six SiO4 tetrahedra and edges with two equivalent MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.04–2.21 Å. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six SiO4 tetrahedra and edges with two equivalent MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.07–2.20 Å. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six SiO4 tetrahedra and edges with two equivalent MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.07–2.18 Å. In the fifth Mg2+ site, Mg2+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Mg–O bond distances ranging from 2.04–2.09 Å. There are eight inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 36–58°. There are a spread of Si–O bond distances ranging from 1.61–1.70 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 34–60°. There are a spread of Si–O bond distances ranging from 1.60–1.69 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 36–61°. There are a spread of Si–O bond distances ranging from 1.60–1.69 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 35–58°. There are a spread of Si–O bond distances ranging from 1.61–1.70 Å. In the fifth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 40–61°. There are a spread of Si–O bond distances ranging from 1.62–1.68 Å. In the sixth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 34–58°. There are a spread of Si–O bond distances ranging from 1.61–1.71 Å. In the seventh Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 41–60°. There are a spread of Si–O bond distances ranging from 1.62–1.69 Å. In the eighth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 34–59°. There are a spread of Si–O bond distances ranging from 1.60–1.70 Å. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+ and two Si4+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two Ca2+ and two Si4+ atoms. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ca2+ and two Si4+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to two Ca2+ and two Si4+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+ and two Si4+ atoms. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to two Ca2+ and two Si4+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+ and two Si4+ atoms. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to two Ca2+ and two Si4+ atoms. In the ninth O2- site, O2- is bonded in a distorted T-shaped geometry to one Ca2+, one Mg2+, and one Si4+ atom. In the tenth O2- site, O2- is bonded in a distorted T-shaped geometry to one Ca2+, one Mg2+, and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a distorted T-shaped geometry to one Ca2+, one Mg2+, and one Si4+ atom. In the twelfth O2- site, O2- is bonded in a distorted T-shaped geometry to one Ca2+, one Mg2+, and one Si4+ atom. In the thirteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Mg2+ and one Si4+ atom. In the fourteenth O2- site, O2- is bonded in a distorted T-shaped geometry to one Ca2+, one Mg2+, and one Si4+ atom. In the fifteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Mg2+ and one Si4+ atom. In the sixteenth O2- site, O2- is bonded in a distorted T-shaped geometry to one Ca2+, one Mg2+, and one Si4+ atom. In the seventeenth O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two Mg2+, and one Si4+ atom. In the eighteenth O2- site, O2- is bonded in a 4-coordinate geometry to three Mg2+ and one Si4+ atom. In the nineteenth O2- site, O2- is bonded in a distorted trigonal pyramidal geometry to three Mg2+ and one Si4+ atom. In the twentieth O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two Mg2+, and one Si4+ atom. In the twenty-first O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two Mg2+, and one Si4+ atom. In the twenty-second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+, two Mg2+, and one Si4+ atom. In the twenty-third O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two Mg2+, and one Si4+ atom. In the twenty-fourth O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two Mg2+, and one Si4+ atom.