Materials Data on K2U7O22 by Materials Project
K2U7O22 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. K1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of K–O bond distances ranging from 2.79–3.33 Å. There are four inequivalent U6+ sites. In the first U6+ site, U6+ is bonded to six O2- atoms to form UO6 octahedra that share corners with four equivalent UO6 octahedra and corners with two equivalent UO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 52°. There are a spread of U–O bond distances ranging from 1.93–2.27 Å. In the second U6+ site, U6+ is bonded to seven O2- atoms to form distorted UO7 pentagonal bipyramids that share a cornercorner with one UO6 octahedra and edges with two equivalent UO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 30°. There are a spread of U–O bond distances ranging from 1.84–2.56 Å. In the third 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 1.91–2.63 Å. In the fourth U6+ site, U6+ is bonded to six O2- atoms to form a mixture of distorted edge and corner-sharing UO6 octahedra. The corner-sharing octahedral tilt angles are 52°. There are a spread of U–O bond distances ranging from 1.80–2.40 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to three U6+ atoms. In the second O2- site, O2- is bonded in a 1-coordinate geometry to three U6+ atoms. In the third O2- site, O2- is bonded in a trigonal planar geometry to three U6+ atoms. In the fourth O2- site, O2- is bonded in a trigonal planar geometry to three U6+ atoms. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to three U6+ atoms. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent K1+ and one U6+ atom. In the seventh O2- site, O2- is bonded in a single-bond geometry to one K1+ and one U6+ atom. In the eighth O2- site, O2- is bonded in a distorted single-bond geometry to one K1+ and one U6+ atom. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+ and two U6+ atoms.