Materials Data on CaNiAsO5 by Materials Project
CaNiAsO5 is Esseneite-like structured and crystallizes in the orthorhombic P2_12_12_1 space group. The structure is three-dimensional. Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.30–2.73 Å. Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with four equivalent AsO4 tetrahedra and edges with two equivalent NiO6 octahedra. There are a spread of Ni–O bond distances ranging from 1.85–2.09 Å. As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with four equivalent NiO6 octahedra. The corner-sharing octahedra tilt angles range from 40–62°. There are a spread of As–O bond distances ranging from 1.70–1.75 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two equivalent Ni3+, and one As5+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ca2+ and one As5+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ca2+, one Ni3+, and one As5+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ca2+, one Ni3+, and one As5+ atom. In the fifth O2- site, O2- is bonded in a trigonal non-coplanar geometry to one Ca2+ and two equivalent Ni3+ atoms.