DOI: 10.17188/1680158
title: Materials Data on Ca2AlCuAs3O19 by Materials Project

description: Ca2CuAlAs2O15AsO4 crystallizes in the triclinic P-1 space group. The structure is two-dimensional and consists of two AsO4 clusters and one Ca2CuAlAs2O15 sheet oriented in the (0, 0, 1) direction. In each AsO4 cluster, As is bonded in a tetrahedral geometry to four O atoms. There are a spread of As–O bond distances ranging from 1.71–1.80 Å. There are four inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one As atom. In the second O site, O is bonded in a single-bond geometry to one As atom. In the third O site, O is bonded in a single-bond geometry to one As atom. In the fourth O site, O is bonded in a single-bond geometry to one As atom. In the Ca2CuAlAs2O15 sheet, 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 2.36–2.57 Å. In the second Ca site, Ca is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of Ca–O bond distances ranging from 2.38–2.86 Å. Cu is bonded to five O atoms to form distorted CuO5 square pyramids that share corners with two AlO6 octahedra and corners with two equivalent AsO4 tetrahedra. The corner-sharing octahedra tilt angles range from 61–63°. There are a spread of Cu–O bond distances ranging from 1.81–2.36 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 two equivalent CuO5 square pyramids and corners with four AsO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.87–1.94 Å. In the second Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with two equivalent CuO5 square pyramids and corners with four AsO4 tetrahedra. There is two shorter (1.90 Å) and four longer (1.93 Å) Al–O bond length. There are two inequivalent As sites. In the first As site, As is bonded to four O atoms to form AsO4 tetrahedra that share corners with two AlO6 octahedra and corners with two equivalent CuO5 square pyramids. The corner-sharing octahedra tilt angles range from 51–52°. There are a spread of As–O bond distances ranging from 1.70–1.74 Å. In the second As site, As is bonded to four O atoms to form AsO4 tetrahedra that share corners with two AlO6 octahedra. The corner-sharing octahedra tilt angles range from 52–53°. There are a spread of As–O bond distances ranging from 1.70–1.75 Å. There are fifteen inequivalent O sites. In the first O site, O is bonded in a 3-coordinate geometry to one Ca, one Cu, and one As atom. In the second O site, O is bonded in a 3-coordinate geometry to one Ca, one Cu, and one As atom. In the third O site, O is bonded in a distorted trigonal planar geometry to one Ca, one Al, and one As atom. In the fourth O site, O is bonded in a distorted trigonal planar geometry to one Ca, one Al, and one As atom. In the fifth O site, O is bonded in a trigonal non-coplanar geometry to two Ca and one As atom. In the sixth O site, O is bonded in a bent 120 degrees geometry to one Al and one As atom. In the seventh O site, O is bonded in a distorted bent 120 degrees geometry to one Ca, one Al, and one As atom. In the eighth O site, O is bonded in a distorted trigonal non-coplanar geometry to two Ca and one As atom. In the ninth O site, O is bonded in a trigonal non-coplanar geometry to one Ca, one Cu, and one Al atom. In the tenth O site, O is bonded in a trigonal non-coplanar geometry to one Ca, one Cu, and one Al atom. In the eleventh O site, O is bonded in a single-bond geometry to one Cu atom. In the twelfth O site, O is bonded in a single-bond geometry to one Ca atom. In the thirteenth O site, O is bonded in a single-bond geometry to one Ca atom. In the fourteenth O site, O is bonded in a distorted single-bond geometry to one Ca atom. In the fifteenth O site, O is bonded in a single-bond geometry to one Ca atom.