Materials Data on CaV(Si2O7)2 by Materials Project
CaV(Si2O7)2 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. Ca is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of Ca–O bond distances ranging from 2.24–2.43 Å. V is bonded to five O atoms to form distorted VO5 trigonal bipyramids that share corners with four SiO4 tetrahedra. There are a spread of V–O bond distances ranging from 1.61–1.92 Å. There are two inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three equivalent SiO4 tetrahedra and a cornercorner with one VO5 trigonal bipyramid. There are a spread of Si–O bond distances ranging from 1.62–1.64 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three equivalent SiO4 tetrahedra and a cornercorner with one VO5 trigonal bipyramid. There are a spread of Si–O bond distances ranging from 1.62–1.65 Å. There are eight inequivalent O sites. In the first O site, O is bonded in a linear geometry to two Si atoms. In the second O site, O is bonded in a bent 120 degrees geometry to two Si atoms. In the third O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the fourth O site, O is bonded in a single-bond geometry to one V atom. In the fifth O site, O is bonded in a distorted L-shaped geometry to one Ca and one O atom. The O–O bond length is 1.28 Å. In the sixth O site, O is bonded in a single-bond geometry to one Ca atom. In the seventh O site, O is bonded in a 3-coordinate geometry to one Ca, one V, and one Si atom. In the eighth O site, O is bonded in a distorted trigonal planar geometry to one Ca, one V, and one Si atom.