Materials Data on Ca6Si2O13 by Materials Project
Ca6Si2O13 crystallizes in the trigonal P3 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 CaO6 octahedra that share corners with two equivalent CaO6 octahedra, corners with three SiO4 tetrahedra, and an edgeedge with one CaO6 octahedra. The corner-sharing octahedra tilt angles range from 59–60°. There are a spread of Ca–O bond distances ranging from 2.33–2.41 Å. In the second Ca site, Ca is bonded to six O atoms to form CaO6 octahedra that share corners with two equivalent CaO6 octahedra, corners with three SiO4 tetrahedra, and an edgeedge with one CaO6 octahedra. The corner-sharing octahedra tilt angles range from 59–60°. There are a spread of Ca–O bond distances ranging from 2.32–2.41 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 2.31–2.90 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 2.31–2.88 Å. There are four inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with six CaO6 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. There is three shorter (1.64 Å) and one longer (1.66 Å) Si–O bond length. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with six CaO6 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–53°. There is three shorter (1.64 Å) and one longer (1.67 Å) Si–O bond length. In the third Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three equivalent CaO6 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 54°. There is three shorter (1.64 Å) and one longer (1.66 Å) Si–O bond length. In the fourth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three equivalent CaO6 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. There is three shorter (1.64 Å) and one longer (1.66 Å) Si–O bond length. There are ten inequivalent O sites. In the first O site, O is bonded in a linear geometry to three equivalent Ca and two Si atoms. In the second O site, O is bonded in a linear geometry to three equivalent Ca and two Si atoms. In the third O site, O is bonded in a trigonal planar geometry to three Ca atoms. In the fourth O site, O is bonded in a distorted rectangular see-saw-like geometry to three Ca and one Si atom. In the fifth 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 sixth 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 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 in a trigonal planar geometry to three Ca atoms. In the ninth O site, O is bonded in a trigonal planar geometry to three Ca atoms. In the tenth O site, O is bonded in a trigonal planar geometry to three Ca atoms.