DOI: 10.17188/1696279
title: Materials Data on Fe2Cu8P4O21 by Materials Project

description: Fe2Cu8P4O21 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with four PO4 tetrahedra, corners with two equivalent CuO5 trigonal bipyramids, edges with two equivalent FeO6 octahedra, and edges with two equivalent CuO5 trigonal bipyramids. There are a spread of Fe–O bond distances ranging from 2.01–2.10 Å. There are three inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded to five O2- atoms to form CuO5 trigonal bipyramids that share corners with two equivalent PO4 tetrahedra, corners with three CuO5 trigonal bipyramids, edges with two equivalent FeO6 octahedra, and edges with two equivalent CuO5 trigonal bipyramids. There are a spread of Cu–O bond distances ranging from 1.91–2.16 Å. In the second Cu2+ site, Cu2+ is bonded to five O2- atoms to form CuO5 trigonal bipyramids that share corners with two equivalent FeO6 octahedra, corners with two equivalent PO4 tetrahedra, a cornercorner with one CuO5 trigonal bipyramid, and edges with four CuO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 51°. There are a spread of Cu–O bond distances ranging from 1.95–2.08 Å. In the third Cu2+ site, Cu2+ is bonded to five O2- atoms to form CuO5 trigonal bipyramids that share corners with four PO4 tetrahedra, a cornercorner with one CuO5 trigonal bipyramid, and edges with three CuO5 trigonal bipyramids. There are a spread of Cu–O bond distances ranging from 1.96–2.16 Å. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent FeO6 octahedra and corners with six CuO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 49°. There are a spread of P–O bond distances ranging from 1.54–1.58 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent FeO6 octahedra and corners with six CuO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 53°. There are a spread of P–O bond distances ranging from 1.53–1.57 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two Cu2+ and one P5+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Cu2+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Cu2+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Fe3+, one Cu2+, and one P5+ atom. In the fifth O2- site, O2- is bonded to two equivalent Fe3+ and two Cu2+ atoms to form corner-sharing OFe2Cu2 trigonal pyramids. In the sixth O2- site, O2- is bonded to four Cu2+ atoms to form distorted corner-sharing OCu4 trigonal pyramids. In the seventh O2- site, O2- is bonded in a square co-planar geometry to four Cu2+ atoms. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Cu2+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Fe3+ and one P5+ atom.