Materials Data on CaAsO4 by Materials Project
CaAsO4 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Ca sites. In the first Ca site, Ca is bonded to six O atoms to form distorted CaO6 octahedra that share corners with six AsO4 tetrahedra and an edgeedge with one CaO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.32–2.45 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 2.40–2.71 Å. 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 four equivalent CaO6 octahedra. The corner-sharing octahedra tilt angles range from 36–63°. There are a spread of As–O bond distances ranging from 1.71–1.73 Å. In the second As site, As is bonded to four O atoms to form AsO4 tetrahedra that share corners with two equivalent CaO6 octahedra. The corner-sharing octahedra tilt angles range from 56–67°. There are a spread of As–O bond distances ranging from 1.71–1.75 Å. There are eight inequivalent O sites. In the first O site, O is bonded in a bent 150 degrees geometry to one Ca and one As atom. In the second O site, O is bonded in a 4-coordinate geometry to three Ca and one As atom. In the third O site, O is bonded in a distorted trigonal planar geometry to two equivalent Ca and one As atom. In the fourth O site, O is bonded in a 2-coordinate geometry to two Ca and one As atom. In the fifth O site, O is bonded in a distorted bent 120 degrees geometry to one Ca and one As atom. In the sixth O site, O is bonded in a 3-coordinate geometry to two Ca and one As atom. In the seventh O site, O is bonded in a 1-coordinate geometry to one Ca and one As atom. In the eighth O site, O is bonded in a distorted trigonal planar geometry to two Ca and one As atom.