Materials Data on K2Fe2P2O7F2 by Materials Project

Abstract

K2Fe2P2O7F2 crystallizes in the orthorhombic Pbcn space group. The structure is three-dimensional. K1+ is bonded in a 8-coordinate geometry to six O2- and two equivalent F1- atoms. There are a spread of K–O bond distances ranging from 2.68–2.96 Å. There are one shorter (2.50 Å) and one longer (2.98 Å) K–F bond lengths. There are two inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded in a distorted square co-planar geometry to four O2- atoms. There are two shorter (2.09 Å) and two longer (2.15 Å) Fe–O bond lengths. In the second Fe2+ site, Fe2+ is bonded in a square co-planar geometry to four O2- atoms. There are two shorter (2.03 Å) and two longer (2.06 Å) Fe–O bond lengths. P5+ is bonded to four O2- and one F1- atom to form corner-sharing PO4F trigonal bipyramids. There are a spread of P–O bond distances ranging from 1.60–1.69 Å. The P–F bond length is 1.83 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to one K1+, two Fe2+, and one P5+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent K1+, one Fe2+, and one P5+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent K1+, one Fe2+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent K1+ and two equivalent P5+ atoms. F1- is bonded in a 2-coordinate geometry to two equivalent K1+ and one P5+ atom.