Materials Data on Ca6Si6O19 by Materials Project

Abstract

Ca6Si6O19 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are four inequivalent Ca sites. In the first Ca site, Ca is bonded to six O atoms to form distorted CaO6 octahedra that share corners with four SiO4 tetrahedra and edges with two equivalent CaO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.31–2.42 Å. In the second Ca site, Ca is bonded to six O atoms to form CaO6 octahedra that share corners with six SiO4 tetrahedra and edges with two equivalent CaO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.38–2.44 Å. In the third Ca site, Ca is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of Ca–O bond distances ranging from 2.33–2.83 Å. In the fourth Ca site, Ca is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of Ca–O bond distances ranging from 2.32–2.78 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 CaO6 octahedra and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 41–60°. There are a spread of Si–O bond distances ranging from 1.62–1.66 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two CaO6 octahedra and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 41–60°. 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 a cornercorner with one CaO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 56°. There are a spread of Si–O bond distances ranging from 1.61–1.64 Å. There are ten inequivalent O sites. In the first O site, O is bonded in a linear geometry to two equivalent Si atoms. In the second O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the third O site, O is bonded in a 4-coordinate geometry to three Ca and one Si atom. In the fourth O site, O is bonded in a 4-coordinate geometry to three Ca and one Si atom. In the fifth O site, O is bonded in a distorted bent 150 degrees geometry to one Ca and two Si atoms. In the sixth O site, O is bonded in a 2-coordinate geometry to one Ca and two Si atoms. 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 trigonal pyramids. 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 trigonal pyramids. 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 tetrahedra. In the tenth O site, O is bonded in a trigonal non-coplanar geometry to three Ca atoms.