DOI: 10.17188/1723513
title: Materials Data on Na3CaMgCr3(SiO3)8 by Materials Project

description: Na3CaMgCr3(SiO3)8 is Esseneite-derived structured and crystallizes in the monoclinic P2 space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Na–O bond distances ranging from 2.38–2.84 Å. In the second Na1+ site, Na1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Na–O bond distances ranging from 2.43–2.80 Å. In the third Na1+ site, Na1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Na–O bond distances ranging from 2.41–2.78 Å. Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.36–2.80 Å. Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six SiO4 tetrahedra and edges with two equivalent CrO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.06–2.11 Å. There are three inequivalent Cr3+ sites. In the first Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six SiO4 tetrahedra and edges with two equivalent CrO6 octahedra. There are a spread of Cr–O bond distances ranging from 1.97–2.09 Å. In the second Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six SiO4 tetrahedra and edges with two equivalent MgO6 octahedra. There are a spread of Cr–O bond distances ranging from 1.99–2.09 Å. In the third Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six SiO4 tetrahedra and edges with two equivalent CrO6 octahedra. There are a spread of Cr–O bond distances ranging from 1.98–2.10 Å. There are four inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one MgO6 octahedra, corners with two CrO6 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 1.60–1.68 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one MgO6 octahedra, corners with two CrO6 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 1.62–1.67 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three CrO6 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 1.60–1.68 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one MgO6 octahedra, corners with two CrO6 octahedra, and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 34–61°. There are a spread of Si–O bond distances ranging from 1.62–1.66 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted T-shaped geometry to one Ca2+, one Mg2+, and one Si4+ atom. In the second O2- site, O2- is bonded in a distorted T-shaped geometry to one Na1+, one Cr3+, and one Si4+ atom. In the third O2- site, O2- is bonded in a distorted T-shaped geometry to one Na1+, one Cr3+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a distorted T-shaped geometry to one Na1+, one Cr3+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, two Cr3+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, one Mg2+, one Cr3+, and one Si4+ atom. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, two Cr3+, and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, one Mg2+, one Cr3+, and one Si4+ atom. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+, one Ca2+, and two Si4+ atoms. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to two Na1+ and two Si4+ atoms. In the eleventh O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+, one Ca2+, and two Si4+ atoms. In the twelfth O2- site, O2- is bonded in a 2-coordinate geometry to two Na1+ and two Si4+ atoms.