DOI: 10.17188/1653901
title: Materials Data on K9(FeO4)2 by Materials Project

description: K9(FeO4)2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are ten inequivalent K sites. In the first K site, K is bonded in a 5-coordinate geometry to five O atoms. There are a spread of K–O bond distances ranging from 2.66–2.86 Å. In the second K site, K is bonded to six O atoms to form distorted KO6 octahedra that share corners with six FeO4 tetrahedra. There are a spread of K–O bond distances ranging from 2.80–3.01 Å. In the third K site, K is bonded to four O atoms to form distorted KO4 tetrahedra that share corners with four FeO4 tetrahedra, corners with two equivalent KO5 trigonal bipyramids, and edges with two equivalent KO5 trigonal bipyramids. There are two shorter (2.63 Å) and two longer (2.76 Å) K–O bond lengths. In the fourth K site, K is bonded in a 5-coordinate geometry to five O atoms. There are a spread of K–O bond distances ranging from 2.68–3.03 Å. In the fifth K site, K is bonded in a 6-coordinate geometry to six O atoms. There are a spread of K–O bond distances ranging from 2.73–3.10 Å. In the sixth K site, K is bonded in a 6-coordinate geometry to six O atoms. There are a spread of K–O bond distances ranging from 2.75–3.09 Å. In the seventh K site, K is bonded in a 5-coordinate geometry to five O atoms. There are a spread of K–O bond distances ranging from 2.59–3.16 Å. In the eighth K site, K is bonded to five O atoms to form distorted KO5 trigonal bipyramids that share a cornercorner with one KO4 tetrahedra, a cornercorner with one FeO4 tetrahedra, an edgeedge with one KO4 tetrahedra, edges with two FeO4 tetrahedra, and an edgeedge with one KO5 trigonal bipyramid. There are a spread of K–O bond distances ranging from 2.68–2.95 Å. In the ninth K site, K is bonded in a 4-coordinate geometry to six O atoms. There are a spread of K–O bond distances ranging from 2.76–3.20 Å. In the tenth K site, K is bonded in a 4-coordinate geometry to four O atoms. There are a spread of K–O bond distances ranging from 2.69–2.81 Å. There are two inequivalent Fe sites. In the first Fe site, Fe is bonded to four O atoms to form FeO4 tetrahedra that share a cornercorner with one KO6 octahedra, a cornercorner with one KO4 tetrahedra, and an edgeedge with one KO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 26°. There are a spread of Fe–O bond distances ranging from 1.88–1.92 Å. In the second Fe site, Fe is bonded to four O atoms to form FeO4 tetrahedra that share corners with two equivalent KO6 octahedra, a cornercorner with one KO4 tetrahedra, a cornercorner with one KO5 trigonal bipyramid, and an edgeedge with one KO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 12–27°. There are a spread of Fe–O bond distances ranging from 1.87–1.92 Å. There are eight inequivalent O sites. In the first O site, O is bonded in a 1-coordinate geometry to five K and one Fe atom. In the second O site, O is bonded in a 1-coordinate geometry to six K and one Fe atom. In the third O site, O is bonded in a 1-coordinate geometry to seven K and one Fe atom. In the fourth O site, O is bonded in a 1-coordinate geometry to six K and one Fe atom. In the fifth O site, O is bonded in a 1-coordinate geometry to six K and one Fe atom. In the sixth O site, O is bonded in a 5-coordinate geometry to five K and one Fe atom. In the seventh O site, O is bonded to six K and one Fe atom to form a mixture of distorted face and edge-sharing OK6Fe pentagonal bipyramids. In the eighth O site, O is bonded in a 1-coordinate geometry to six K and one Fe atom.