Materials Data on K2U2O7 by Materials Project

Abstract

K2U2O7 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of K–O bond distances ranging from 2.70–3.11 Å. In the second K1+ site, K1+ is bonded to six O2- atoms to form distorted KO6 octahedra that share corners with three UO6 octahedra and edges with two equivalent KO6 octahedra. The corner-sharing octahedra tilt angles range from 60–61°. There are a spread of K–O bond distances ranging from 2.66–2.87 Å. There are three inequivalent U6+ sites. In the first U6+ site, U6+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of U–O bond distances ranging from 1.87–2.66 Å. In the second U6+ site, U6+ is bonded to six O2- atoms to form UO6 octahedra that share corners with two equivalent UO6 octahedra and corners with four equivalent KO6 octahedra. The corner-sharing octahedra tilt angles range from 49–61°. There are a spread of U–O bond distances ranging from 1.90–2.21 Å. In the third U6+ site, U6+ is bonded to six O2- atoms to form UO6 octahedra that share corners with two equivalent KO6 octahedra and corners with two equivalent UO6 octahedra. The corner-sharing octahedra tilt angles range from 49–60°. There are a spread of U–O bond distances ranging from 1.90–2.22 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to three K1+ and one U6+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one K1+ and three U6+ atoms. In the third O2- site, O2- is bonded in a 1-coordinate geometry to three K1+ and one U6+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to three U6+ atoms. In the fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three K1+ and one U6+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to three U6+ atoms. In the seventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three K1+ and one U6+ atom.