Materials Data on Ca6AlCr3(SiO4)6 by Materials Project

Abstract

Ca6Cr3Al(SiO4)6 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are four inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.37–2.54 Å. In the second Ca2+ site, Ca2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are four shorter (2.37 Å) and four longer (2.52 Å) Ca–O bond lengths. In the third Ca2+ site, Ca2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.36–2.53 Å. In the fourth Ca2+ site, Ca2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.36–2.54 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. There are two shorter (2.02 Å) and four longer (2.03 Å) Cr–O bond lengths. In the second Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six SiO4 tetrahedra. There are two shorter (2.02 Å) and four longer (2.03 Å) Cr–O bond lengths. In the third Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six SiO4 tetrahedra. There are four shorter (2.02 Å) and two longer (2.03 Å) Cr–O bond lengths. Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six SiO4 tetrahedra. There is four shorter (1.96 Å) and two longer (1.97 Å) Al–O bond length. There are four inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four CrO6 octahedra. The corner-sharing octahedra tilt angles range from 46–47°. All Si–O bond lengths are 1.66 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent CrO6 octahedra and corners with two equivalent AlO6 octahedra. The corner-sharing octahedra tilt angles range from 44–46°. There is two shorter (1.66 Å) and two longer (1.67 Å) Si–O bond length. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one AlO6 octahedra and corners with three CrO6 octahedra. The corner-sharing octahedra tilt angles range from 45–47°. There is three shorter (1.66 Å) and one longer (1.67 Å) Si–O bond length. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one AlO6 octahedra and corners with three CrO6 octahedra. The corner-sharing octahedra tilt angles range from 45–47°. There is three shorter (1.66 Å) and one longer (1.67 Å) Si–O bond length. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Al3+, and one Si4+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Cr3+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Al3+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Cr3+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Cr3+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Al3+, and one Si4+ atom. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Cr3+, and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Cr3+, and one Si4+ atom. In the ninth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Cr3+, and one Si4+ atom. In the tenth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Cr3+, and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Cr3+, and one Si4+ atom. In the twelfth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Cr3+, and one Si4+ atom.