DOI: 10.17188/1681488
title: Materials Data on Ca4Al5CrSi6(HO13)2 by Materials Project

description: Ca4CrAl5Si6(HO13)2 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.28–2.54 Å. In the second Ca2+ site, Ca2+ is bonded in a 1-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.26–2.87 Å. Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with four SiO4 tetrahedra and edges with four AlO6 octahedra. There are a spread of Cr–O bond distances ranging from 1.97–2.02 Å. There are four inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with four SiO4 tetrahedra and edges with two equivalent AlO6 octahedra. There is four shorter (1.88 Å) and two longer (1.95 Å) Al–O bond length. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with four SiO4 tetrahedra and edges with two equivalent AlO6 octahedra. There is four shorter (1.88 Å) and two longer (1.95 Å) Al–O bond length. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with four SiO4 tetrahedra, edges with two equivalent CrO6 octahedra, and edges with two equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.86–1.96 Å. In the fourth Al3+ site, Al3+ is bonded to six O2- atoms to form distorted AlO6 octahedra that share corners with five SiO4 tetrahedra, an edgeedge with one CrO6 octahedra, and an edgeedge with one AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.80–2.24 Å. There are three inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three AlO6 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 30–53°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one CrO6 octahedra, corners with three AlO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 51–60°. There are a spread of Si–O bond distances ranging from 1.59–1.67 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one CrO6 octahedra and corners with five AlO6 octahedra. The corner-sharing octahedra tilt angles range from 48–55°. There are a spread of Si–O bond distances ranging from 1.65–1.68 Å. H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. There are thirteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to one Ca2+, two Al3+, and one H1+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ca2+ and one Si4+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two Ca2+, one Al3+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to two Ca2+, one Al3+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, one Cr3+, one Al3+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ca2+, one Al3+, and one Si4+ atom. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ca2+, one Al3+, and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, one Cr3+, one Al3+, and one Si4+ atom. In the ninth O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two Al3+, and one Si4+ atom. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to two Al3+ and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the twelfth O2- site, O2- is bonded in a bent 150 degrees geometry to one Al3+ and one Si4+ atom. In the thirteenth O2- site, O2- is bonded in a trigonal non-coplanar geometry to one Cr3+ and two Al3+ atoms.