Materials Data on MgCuF5 by Materials Project

Abstract

MgCuF5 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Mg2+ is bonded to seven F1- atoms to form distorted MgF7 pentagonal bipyramids that share corners with four equivalent CuF6 octahedra, edges with two equivalent CuF6 octahedra, and edges with two equivalent MgF7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 13–46°. There are a spread of Mg–F bond distances ranging from 1.95–2.34 Å. Cu3+ is bonded to six F1- atoms to form CuF6 octahedra that share corners with two equivalent CuF6 octahedra, corners with four equivalent MgF7 pentagonal bipyramids, and edges with two equivalent MgF7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 40°. There are a spread of Cu–F bond distances ranging from 1.88–1.97 Å. There are five inequivalent F1- sites. In the first F1- site, F1- is bonded in a 3-coordinate geometry to two equivalent Mg2+ and one Cu3+ atom. In the second F1- site, F1- is bonded in a 3-coordinate geometry to two equivalent Mg2+ and one Cu3+ atom. In the third F1- site, F1- is bonded in a bent 150 degrees geometry to one Mg2+ and one Cu3+ atom. In the fourth F1- site, F1- is bonded in a linear geometry to one Mg2+ and one Cu3+ atom. In the fifth F1- site, F1- is bonded in a 3-coordinate geometry to one Mg2+ and two equivalent Cu3+ atoms.