Materials Data on FeNiAg2F7 by Materials Project

Abstract

FeNiAg2F7 crystallizes in the orthorhombic Imm2 space group. The structure is three-dimensional. Fe3+ is bonded to six F1- atoms to form FeF6 octahedra that share corners with two equivalent FeF6 octahedra, corners with four equivalent NiF6 octahedra, and edges with four equivalent AgF8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 38–40°. There are a spread of Fe–F bond distances ranging from 1.94–2.01 Å. Ni2+ is bonded to six F1- atoms to form NiF6 octahedra that share corners with two equivalent AgF8 hexagonal bipyramids, corners with four equivalent FeF6 octahedra, and edges with two equivalent AgF8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 38°. There are a spread of Ni–F bond distances ranging from 2.02–2.05 Å. There are two inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded to eight F1- atoms to form distorted AgF8 hexagonal bipyramids that share corners with two equivalent AgF8 hexagonal bipyramids, corners with two equivalent NiF6 octahedra, edges with two equivalent NiF6 octahedra, and edges with four equivalent FeF6 octahedra. The corner-sharing octahedral tilt angles are 56°. There are a spread of Ag–F bond distances ranging from 2.31–2.93 Å. In the second Ag1+ site, Ag1+ is bonded in a distorted body-centered cubic geometry to eight F1- atoms. There are four shorter (2.50 Å) and four longer (2.89 Å) Ag–F bond lengths. There are six inequivalent F1- sites. In the first F1- site, F1- is bonded to one Ni2+ and three Ag1+ atoms to form a mixture of distorted corner and edge-sharing FNiAg3 tetrahedra. In the second F1- site, F1- is bonded in a 2-coordinate geometry to one Fe3+, one Ni2+, and two Ag1+ atoms. In the third F1- site, F1- is bonded in a 2-coordinate geometry to one Fe3+, one Ni2+, and two Ag1+ atoms. In the fourth F1- site, F1- is bonded in a distorted bent 150 degrees geometry to two equivalent Fe3+ and two equivalent Ag1+ atoms. In the fifth F1- site, F1- is bonded to one Ni2+ and three Ag1+ atoms to form a mixture of distorted corner and edge-sharing FNiAg3 tetrahedra. In the sixth F1- site, F1- is bonded in a distorted bent 150 degrees geometry to two equivalent Fe3+ and two equivalent Ag1+ atoms.