DOI: 10.17188/1318343
title: Materials Data on CaCu2(As2O7)2 by Materials Project

description: CaCu2(As2O7)2 crystallizes in the monoclinic P2_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 2.27–2.97 Å. There are two inequivalent Cu3+ sites. In the first Cu3+ site, Cu3+ is bonded to five O2- atoms to form distorted CuO5 trigonal bipyramids that share corners with five AsO4 tetrahedra. There are a spread of Cu–O bond distances ranging from 1.83–2.44 Å. In the second Cu3+ site, Cu3+ is bonded to five O2- atoms to form distorted CuO5 square pyramids that share corners with five AsO4 tetrahedra. There are a spread of Cu–O bond distances ranging from 1.84–2.43 Å. There are four inequivalent As5+ sites. In the first As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share a cornercorner with one AsO4 tetrahedra and corners with two equivalent CuO5 trigonal bipyramids. There are a spread of As–O bond distances ranging from 1.66–1.80 Å. In the second As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with two equivalent CuO5 square pyramids and a cornercorner with one AsO4 tetrahedra. There are a spread of As–O bond distances ranging from 1.65–1.81 Å. In the third As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share a cornercorner with one CuO5 square pyramid, a cornercorner with one AsO4 tetrahedra, and corners with two equivalent CuO5 trigonal bipyramids. There are a spread of As–O bond distances ranging from 1.67–1.77 Å. In the fourth As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with two equivalent CuO5 square pyramids, a cornercorner with one AsO4 tetrahedra, and a cornercorner with one CuO5 trigonal bipyramid. There are a spread of As–O bond distances ranging from 1.67–1.79 Å. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Cu3+, and one As5+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cu3+ and one As5+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+, one Cu3+, and one As5+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cu3+ and one As5+ atom. In the fifth O2- site, O2- is bonded in a bent 120 degrees geometry to one Ca2+ and one As5+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ca2+ and one As5+ atom. In the seventh O2- site, O2- is bonded in a bent 120 degrees geometry to two As5+ atoms. In the eighth O2- site, O2- is bonded in a bent 120 degrees geometry to two As5+ atoms. In the ninth O2- site, O2- is bonded in a bent 120 degrees geometry to one Ca2+, one Cu3+, and one As5+ atom. In the tenth O2- site, O2- is bonded in a bent 120 degrees geometry to one Cu3+ and one As5+ atom. In the eleventh O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Cu3+, and one As5+ atom. In the twelfth O2- site, O2- is bonded in a bent 120 degrees geometry to one Cu3+ and one As5+ atom. In the thirteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Cu3+, and one As5+ atom. In the fourteenth O2- site, O2- is bonded in a 1-coordinate geometry to one Ca2+, one Cu3+, and one As5+ atom.