Materials Data on CaCoSi2O7 by Materials Project

Abstract

CaCoSi2O7 crystallizes in the orthorhombic Cmm2 space group. The structure is three-dimensional. Ca2+ is bonded in a 6-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.28–2.91 Å. Co4+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with four SiO4 tetrahedra. There is two shorter (1.83 Å) and two longer (1.87 Å) Co–O bond length. There are two 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 SiO4 tetrahedra and corners with two equivalent CoO4 tetrahedra. There is three shorter (1.63 Å) and one longer (1.70 Å) Si–O bond length. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one SiO4 tetrahedra and corners with two equivalent CoO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ca2+, one Co4+, and one Si4+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Co4+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ca2+ and one Si4+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Ca2+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms. In the sixth O2- site, O2- is bonded in a distorted tetrahedral geometry to two equivalent Ca2+ and two equivalent Si4+ atoms.