The Synthesis and Crystal Structure of U7O2Se12

The new compound U7O2Se12 was synthesized at 1173 K as a result of both unintentional and intentional oxygen contamination. The composition balances with formal charges of +4, –2, and –2 for U, O, and Se, respectively. U7O2Se12 crystallizes with one formula unit in space group C-P of the hexagonal system in a cell of dimensions a = 11.3222(4) A, c = 4.1362(1) A. The structure of U7O2Se12 closely resembles that of the An7Te12 (An = Th, U) compounds, but contains cavities, in which oxygen atoms are coordinated to three uranium atoms in a trigonal planar arrangement. It is not known if other members of the An7Q12 family (An = Th, U; Q = S, Se, Te) are actually An7O2Q12 compounds.