DOI: 10.17188/1709175
title: Materials Data on Ca7Si6CO23 by Materials Project

description: Ca7Si6CO23 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are four inequivalent Ca sites. In the first Ca site, Ca is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Ca–O bond distances ranging from 2.31–2.50 Å. In the second Ca site, Ca is bonded in a 6-coordinate geometry to seven O atoms. There are a spread of Ca–O bond distances ranging from 2.31–2.87 Å. In the third Ca site, Ca is bonded in a 9-coordinate geometry to nine O atoms. There are a spread of Ca–O bond distances ranging from 2.41–3.02 Å. In the fourth Ca site, Ca is bonded to six O atoms to form distorted CaO6 octahedra that share corners with six SiO4 tetrahedra. There are a spread of Ca–O bond distances ranging from 2.38–2.45 Å. There are three inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent CaO6 octahedra and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–58°. There are a spread of Si–O bond distances ranging from 1.61–1.67 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent CaO6 octahedra and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 51–58°. There are a spread of Si–O bond distances ranging from 1.62–1.67 Å. In the third Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent CaO6 octahedra and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 61–62°. There is two shorter (1.63 Å) and two longer (1.65 Å) Si–O bond length. C is bonded in a trigonal planar geometry to three O atoms. There is two shorter (1.28 Å) and one longer (1.32 Å) C–O bond length. There are fourteen inequivalent O sites. In the first O site, O is bonded in a bent 150 degrees geometry to one Ca and two equivalent Si atoms. In the second O site, O is bonded in a distorted bent 150 degrees geometry to one Ca and two equivalent 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 bent 150 degrees geometry to one Ca and two Si atoms. In the fifth O site, O is bonded in a distorted trigonal planar geometry to two Ca and one Si atom. In the sixth O site, O is bonded in a distorted trigonal planar geometry to two Ca and one Si atom. In the seventh O site, O is bonded to three Ca and one Si atom to form a mixture of distorted edge and corner-sharing OCa3Si tetrahedra. In the eighth O site, O is bonded to three Ca and one Si atom to form a mixture of distorted edge and corner-sharing OCa3Si tetrahedra. In the ninth O site, O is bonded to three Ca and one Si atom to form a mixture of distorted edge and corner-sharing OCa3Si trigonal pyramids. In the tenth O site, O is bonded to three Ca and one Si atom to form a mixture of distorted edge and corner-sharing OCa3Si tetrahedra. In the eleventh O site, O is bonded in a bent 120 degrees geometry to two equivalent Ca atoms. In the twelfth O site, O is bonded in a distorted bent 150 degrees geometry to two equivalent Ca atoms. In the thirteenth O site, O is bonded in a distorted single-bond geometry to three Ca and one C atom. In the fourteenth O site, O is bonded in a 1-coordinate geometry to two Ca and one C atom.