Materials Data on CaCr2(Si2O5)4 by Materials Project

Abstract

CaCr2(Si2O5)4 crystallizes in the tetragonal P-42_1c space group. The structure is three-dimensional. Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are four shorter (2.41 Å) and four longer (2.68 Å) Ca–O bond lengths. Cr3+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There is two shorter (1.87 Å) and two longer (1.97 Å) Cr–O bond length. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.62–1.66 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ca2+ and two Si4+ atoms. In the third O2- site, O2- is bonded in a linear geometry to two Si4+ atoms. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cr3+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+, one Cr3+, and one Si4+ atom.