Materials Data on BaU11(GeO19)2 by Materials Project
BaU11(GeO19)2 crystallizes in the trigonal P-31c space group. The structure is three-dimensional. Ba2+ is bonded in a 6-coordinate geometry to six equivalent O2- atoms. All Ba–O bond lengths are 2.81 Å. There are three inequivalent U6+ sites. In the first U6+ site, U6+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing UO6 octahedra. There are three shorter (2.06 Å) and three longer (2.14 Å) U–O bond lengths. 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, corners with two equivalent UO7 pentagonal bipyramids, a cornercorner with one GeO4 tetrahedra, an edgeedge with one UO6 octahedra, and edges with two UO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 35°. There are a spread of U–O bond distances ranging from 1.83–2.48 Å. In the third U6+ site, U6+ is bonded to seven O2- atoms to form distorted UO7 pentagonal bipyramids that share corners with two equivalent UO6 octahedra, corners with two equivalent UO7 pentagonal bipyramids, corners with two equivalent GeO4 tetrahedra, and edges with two equivalent UO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 31°. There are a spread of U–O bond distances ranging from 1.81–2.46 Å. Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with six UO7 pentagonal bipyramids and a cornercorner with one GeO4 tetrahedra. There is one shorter (1.74 Å) and three longer (1.77 Å) Ge–O bond length. There are eight 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 distorted trigonal planar geometry to three equivalent U6+ atoms. In the third O2- site, O2- is bonded in a distorted single-bond geometry to one Ba2+ and one U6+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent U6+ atoms. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to three U6+ atoms. In the sixth O2- site, O2- is bonded in a single-bond geometry to one U6+ atom. In the seventh O2- site, O2- is bonded in a linear geometry to two equivalent Ge4+ atoms. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to two U6+ and one Ge4+ atom.