Materials Data on K5U2O4F9 by Materials Project

Abstract

K5U2O4F9 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are three inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 8-coordinate geometry to two O2- and six F1- atoms. There are one shorter (2.86 Å) and one longer (3.17 Å) K–O bond lengths. There are a spread of K–F bond distances ranging from 2.71–2.91 Å. In the second K1+ site, K1+ is bonded in a 8-coordinate geometry to three O2- and five F1- atoms. There are a spread of K–O bond distances ranging from 2.82–3.21 Å. There are a spread of K–F bond distances ranging from 2.63–2.96 Å. In the third K1+ site, K1+ is bonded to two equivalent O2- and four F1- atoms to form KO2F4 octahedra that share corners with six equivalent UO2F5 pentagonal bipyramids. Both K–O bond lengths are 2.86 Å. There are two shorter (2.56 Å) and two longer (2.69 Å) K–F bond lengths. U6+ is bonded to two O2- and five F1- atoms to form UO2F5 pentagonal bipyramids that share corners with three equivalent KO2F4 octahedra and a cornercorner with one UO2F5 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 32–36°. Both U–O bond lengths are 1.85 Å. There are a spread of U–F bond distances ranging from 2.26–2.41 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to three K1+ and one U6+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to three K1+ and one U6+ atom. There are five inequivalent F1- sites. In the first F1- site, F1- is bonded in a 4-coordinate geometry to two equivalent K1+ and two equivalent U6+ atoms. In the second F1- site, F1- is bonded in a 4-coordinate geometry to three K1+ and one U6+ atom. In the third F1- site, F1- is bonded in a 4-coordinate geometry to three K1+ and one U6+ atom. In the fourth F1- site, F1- is bonded in a 4-coordinate geometry to three K1+ and one U6+ atom. In the fifth F1- site, F1- is bonded in a 4-coordinate geometry to three K1+ and one U6+ atom.