Materials Data on CaNiF5 by Materials Project

Abstract

CaNiF5 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Ca2+ is bonded to seven F1- atoms to form CaF7 pentagonal bipyramids that share corners with four equivalent NiF6 octahedra, edges with two equivalent NiF6 octahedra, and edges with two equivalent CaF7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 14–44°. There are a spread of Ca–F bond distances ranging from 2.23–2.44 Å. Ni3+ is bonded to six F1- atoms to form NiF6 octahedra that share corners with two equivalent NiF6 octahedra, corners with four equivalent CaF7 pentagonal bipyramids, and edges with two equivalent CaF7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 31°. There are a spread of Ni–F bond distances ranging from 1.85–2.00 Å. There are five inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted trigonal non-coplanar geometry to two equivalent Ca2+ and one Ni3+ atom. In the second F1- site, F1- is bonded in a 3-coordinate geometry to two equivalent Ca2+ and one Ni3+ atom. In the third F1- site, F1- is bonded in a bent 150 degrees geometry to one Ca2+ and one Ni3+ atom. In the fourth F1- site, F1- is bonded in a linear geometry to one Ca2+ and one Ni3+ atom. In the fifth F1- site, F1- is bonded in a 3-coordinate geometry to one Ca2+ and two equivalent Ni3+ atoms.