DOI: 10.17188/1717966
title: Materials Data on KFeSO4F by Materials Project

description: KFeSO4F crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 8-coordinate geometry to six O2- and two F1- atoms. There are a spread of K–O bond distances ranging from 2.69–3.23 Å. There are one shorter (2.69 Å) and one longer (2.79 Å) K–F bond lengths. In the second K1+ site, K1+ is bonded in a 9-coordinate geometry to seven O2- and two F1- atoms. There are a spread of K–O bond distances ranging from 2.71–3.30 Å. There are one shorter (2.94 Å) and one longer (3.04 Å) K–F bond lengths. There are three inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded to four O2- and two F1- atoms to form FeO4F2 octahedra that share corners with four FeO4F2 octahedra and corners with four SO4 tetrahedra. The corner-sharing octahedra tilt angles range from 51–59°. There are a spread of Fe–O bond distances ranging from 2.14–2.44 Å. Both Fe–F bond lengths are 2.01 Å. In the second Fe2+ site, Fe2+ is bonded to four O2- and two equivalent F1- atoms to form FeO4F2 octahedra that share corners with two equivalent FeO4F2 octahedra, corners with four SO4 tetrahedra, and an edgeedge with one FeO4F2 octahedra. The corner-sharing octahedral tilt angles are 58°. There are two shorter (2.14 Å) and two longer (2.21 Å) Fe–O bond lengths. Both Fe–F bond lengths are 2.06 Å. In the third Fe2+ site, Fe2+ is bonded to four O2- and two equivalent F1- atoms to form FeO4F2 octahedra that share corners with two equivalent FeO4F2 octahedra, corners with four SO4 tetrahedra, and an edgeedge with one FeO4F2 octahedra. The corner-sharing octahedral tilt angles are 59°. There are two shorter (2.15 Å) and two longer (2.22 Å) Fe–O bond lengths. Both Fe–F bond lengths are 2.03 Å. There are two inequivalent S6+ sites. In the first S6+ site, S6+ is bonded to four O2- atoms to form SO4 tetrahedra that share corners with four FeO4F2 octahedra. The corner-sharing octahedra tilt angles range from 47–55°. There are a spread of S–O bond distances ranging from 1.47–1.52 Å. In the second S6+ site, S6+ is bonded to four O2- atoms to form SO4 tetrahedra that share corners with four FeO4F2 octahedra. The corner-sharing octahedra tilt angles range from 39–66°. There are a spread of S–O bond distances ranging from 1.48–1.52 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Fe2+, and one S6+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Fe2+, and one S6+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to three K1+ and one S6+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to one K1+, two equivalent Fe2+, and one S6+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Fe2+, and one S6+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to two K1+, one Fe2+, and one S6+ atom. In the seventh O2- site, O2- is bonded in a distorted single-bond geometry to three K1+ and one S6+ atom. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to one K1+, two Fe2+, and one S6+ atom. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a 2-coordinate geometry to two K1+ and two Fe2+ atoms. In the second F1- site, F1- is bonded in a 2-coordinate geometry to two K1+ and two Fe2+ atoms.