Materials Data on Ca2Al2FeSi3O13 by Materials Project

Abstract

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 6-coordinate geometry to six O atoms. There are a spread of Ca–O bond distances ranging from 2.33–2.57 Å. In the second Ca site, Ca is bonded in a 1-coordinate geometry to ten O atoms. There are a spread of Ca–O bond distances ranging from 2.28–3.06 Å. Fe is bonded to six O atoms to form distorted FeO6 octahedra that share corners with five SiO4 tetrahedra and edges with two equivalent AlO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.92–2.33 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with four SiO4 tetrahedra, edges with two equivalent FeO6 octahedra, and edges with two equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.84–2.01 Å. In the second Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with four SiO4 tetrahedra and edges with two equivalent AlO6 octahedra. There is four shorter (1.86 Å) and two longer (1.98 Å) Al–O bond length. 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 FeO6 octahedra, corners with two equivalent AlO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 55°. There is one shorter (1.60 Å) and three 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 a cornercorner with one FeO6 octahedra, corners with two equivalent AlO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 36–53°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the third Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent FeO6 octahedra and corners with four AlO6 octahedra. The corner-sharing octahedra tilt angles range from 47–53°. There is three shorter (1.65 Å) and one longer (1.68 Å) Si–O bond length. There are ten inequivalent O sites. In the first O site, O is bonded in a 3-coordinate geometry to two equivalent Al and one Si atom. In the second O site, O is bonded in a distorted trigonal planar geometry to two Ca and one Si atom. In the third O site, O is bonded in a bent 150 degrees geometry to two equivalent Ca, one Fe, and one Si atom. In the fourth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the fifth O site, O is bonded in a distorted trigonal non-coplanar geometry to one Ca and two equivalent Al atoms. In the sixth O site, O is bonded to one Ca, one Fe, one Al, and one Si atom to form a mixture of distorted corner and edge-sharing OCaAlFeSi tetrahedra. In the seventh O site, O is bonded in a 4-coordinate geometry to two equivalent Ca, one Fe, and one Si atom. In the eighth O site, O is bonded in a 3-coordinate geometry to two Ca, one Al, and one Si atom. In the ninth O site, O is bonded in a trigonal non-coplanar geometry to one Fe and two equivalent Al atoms. In the tenth O site, O is bonded in a 4-coordinate geometry to one Ca, two equivalent Al, and one Si atom.