DOI: 10.17188/1677974
title: Materials Data on Ca2Al2FeSi3O13 by Materials Project

description: Ca2FeAl2Si3O13 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are two inequivalent Ca sites. In the first 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 2.30–2.85 Å. In the second Ca site, Ca is bonded to six O atoms to form distorted CaO6 pentagonal pyramids that share corners with two equivalent FeO6 octahedra, corners with two equivalent CaO6 pentagonal pyramids, corners with two equivalent AlO4 tetrahedra, corners with two equivalent AlO4 trigonal pyramids, and an edgeedge with one SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Ca–O bond distances ranging from 2.32–2.42 Å. Fe is bonded to six O atoms to form distorted FeO6 octahedra that share corners with two equivalent CaO6 pentagonal pyramids, corners with two equivalent SiO4 trigonal pyramids, edges with two equivalent FeO6 octahedra, and edges with two equivalent AlO4 trigonal pyramids. There are a spread of Fe–O bond distances ranging from 1.80–2.31 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded to four O atoms to form AlO4 trigonal pyramids that share corners with two equivalent CaO6 pentagonal pyramids, a cornercorner with one SiO4 tetrahedra, a cornercorner with one SiO4 trigonal pyramid, and edges with two equivalent FeO6 octahedra. There are a spread of Al–O bond distances ranging from 1.80–1.83 Å. In the second Al site, Al is bonded to four O atoms to form AlO4 tetrahedra that share corners with two equivalent CaO6 pentagonal pyramids and corners with four SiO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.73–1.82 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 three equivalent AlO4 tetrahedra, a cornercorner with one SiO4 trigonal pyramid, and an edgeedge with one CaO6 pentagonal pyramid. There are a spread of Si–O bond distances ranging from 1.61–1.68 Å. In the second Si site, Si is bonded to four O atoms to form distorted SiO4 trigonal pyramids that share corners with two equivalent FeO6 octahedra, corners with three SiO4 tetrahedra, and a cornercorner with one AlO4 trigonal pyramid. The corner-sharing octahedral tilt angles are 56°. There is two shorter (1.66 Å) and two longer (1.68 Å) Si–O bond length. In the third Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one AlO4 tetrahedra, a cornercorner with one AlO4 trigonal pyramid, and corners with two equivalent SiO4 trigonal pyramids. There is two shorter (1.62 Å) and two longer (1.69 Å) Si–O bond length. There are ten inequivalent O sites. In the first O site, O is bonded in a 2-coordinate geometry to one Ca and two Si atoms. In the second O site, O is bonded in a bent 120 degrees geometry to one Al and one Si atom. In the third O site, O is bonded in a distorted water-like geometry to one Ca, one Al, and one Si atom. In the fourth O site, O is bonded in a bent 120 degrees geometry to two Si atoms. In the fifth O site, O is bonded in a water-like geometry to two equivalent Fe atoms. In the sixth O site, O is bonded in a 4-coordinate geometry to two equivalent Fe, one Al, and one Si atom. In the seventh O site, O is bonded in a square co-planar geometry to four Ca atoms. In the eighth O site, O is bonded in a 4-coordinate geometry to two Ca, one Fe, and one Al atom. In the ninth O site, O is bonded in a bent 150 degrees geometry to one Al and one Si atom. In the tenth O site, O is bonded in a 3-coordinate geometry to one Ca, one Al, and one Si atom.