DOI: 10.17188/1681409
title: Materials Data on K2U2Cr2O15F2 by Materials Project

description: (KUCrO7F)4O2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional and consists of two oxygen molecules and one KUCrO7F framework. In the KUCrO7F framework, there are two inequivalent K sites. In the first K site, K is bonded in a 8-coordinate geometry to six O and one F atom. There are a spread of K–O bond distances ranging from 2.80–3.01 Å. The K–F bond length is 2.87 Å. In the second K site, K is bonded in a 10-coordinate geometry to nine O and one F atom. There are a spread of K–O bond distances ranging from 2.83–3.39 Å. The K–F bond length is 3.15 Å. There are two inequivalent U sites. In the first U site, U is bonded to five O and two F atoms to form distorted UO5F2 pentagonal bipyramids that share corners with three CrO4 tetrahedra and an edgeedge with one UO5F2 pentagonal bipyramid. There are a spread of U–O bond distances ranging from 1.82–2.34 Å. There are one shorter (2.36 Å) and one longer (2.38 Å) U–F bond lengths. In the second U site, U is bonded to five O and two F atoms to form UO5F2 pentagonal bipyramids that share corners with three CrO4 tetrahedra and an edgeedge with one UO5F2 pentagonal bipyramid. There are a spread of U–O bond distances ranging from 1.82–2.35 Å. There are one shorter (2.34 Å) and one longer (2.38 Å) U–F bond lengths. There are two inequivalent Cr sites. In the first Cr site, Cr is bonded to four O atoms to form CrO4 tetrahedra that share corners with three UO5F2 pentagonal bipyramids. There are a spread of Cr–O bond distances ranging from 1.62–1.69 Å. In the second Cr site, Cr is bonded to four O atoms to form CrO4 tetrahedra that share corners with three UO5F2 pentagonal bipyramids. There are a spread of Cr–O bond distances ranging from 1.61–1.69 Å. There are fourteen inequivalent O sites. In the first O site, O is bonded in a distorted single-bond geometry to two equivalent K and one U atom. In the second O site, O is bonded in a distorted single-bond geometry to one K and one U atom. In the third O site, O is bonded in a distorted single-bond geometry to one K and one U atom. In the fourth O site, O is bonded in a distorted single-bond geometry to two equivalent K and one U atom. In the fifth O site, O is bonded in a 1-coordinate geometry to one K, one U, and one Cr atom. In the sixth O site, O is bonded in a distorted bent 150 degrees geometry to one U and one Cr atom. In the seventh O site, O is bonded in a 2-coordinate geometry to one K, one U, and one Cr atom. In the eighth O site, O is bonded in a distorted single-bond geometry to two equivalent K and one Cr atom. In the ninth O site, O is bonded in a distorted bent 150 degrees geometry to one U and one Cr atom. In the tenth O site, O is bonded in a 1-coordinate geometry to one K, one U, and one Cr atom. In the eleventh O site, O is bonded in a distorted bent 150 degrees geometry to one U and one Cr atom. In the twelfth O site, O is bonded in a distorted single-bond geometry to two equivalent K and one Cr atom. In the thirteenth O site, O is bonded in a single-bond geometry to one K atom. In the fourteenth O site, O is bonded in a single-bond geometry to one K atom. There are two inequivalent F sites. In the first F site, F is bonded in a distorted trigonal non-coplanar geometry to one K and two U atoms. In the second F site, F is bonded in a trigonal non-coplanar geometry to one K and two U atoms.