Materials Data on UH5Se2O9 by Materials Project
UHSe2O9(H2)2 crystallizes in the monoclinic P2_1/c space group. The structure is two-dimensional and consists of eight hydrogen molecules and one UHSe2O9 sheet oriented in the (-1, 0, 2) direction. In the UHSe2O9 sheet, U5+ is bonded to seven O2- atoms to form distorted UO7 pentagonal bipyramids that share corners with three equivalent SeO4 tetrahedra. There are a spread of U–O bond distances ranging from 1.79–2.47 Å. H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. There are two inequivalent Se4+ sites. In the first Se4+ site, Se4+ is bonded to four O2- atoms to form SeO4 tetrahedra that share corners with three equivalent UO7 pentagonal bipyramids. There are a spread of Se–O bond distances ranging from 1.63–1.70 Å. In the second Se4+ site, Se4+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There are a spread of Se–O bond distances ranging from 1.70–1.79 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one U5+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U5+ and one Se4+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one U5+ and one Se4+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U5+ and one Se4+ atom. In the fifth O2- site, O2- is bonded in a distorted water-like geometry to one H1+ and one Se4+ atom. In the sixth O2- site, O2- is bonded in a single-bond geometry to one Se4+ atom. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to one U5+ and one Se4+ atom. In the eighth O2- site, O2- is bonded in a single-bond geometry to one U5+ atom. In the ninth O2- site, O2- is bonded in a bent 150 degrees geometry to one U5+ and one Se4+ atom.