Redetermination of di-μ-hydroxido-bis-[diaquachloridodioxidouranium(VI)] from single-crystal synchrotron data

Abstract

The title compound, [(UO2)2Cl2(OH) 2(H2O)4], was obtained unintentionally as the product of an attempted reaction between uranium(VI) oxide dihydrate, UO 3·2H2O, and hydrogen bis-(trifluoro-methyl-sulfon- yl)imide (HTf2N), in an experiment to obtain crystals of uranyl bis-(trifluoro-methyl-sulfon-yl)imide, UO2(Tf2N) 2·xH2O. The structure consists of neutral dimers of uranyl (UO22+) units, double bridged by OH- anions. Each uranyl unit is surrounded by one Cl and four O atoms, which form an irregular penta-gon, in a plane perpendicular to the linear uranyl groups. The coordination geometry around each U atom can be considered to be distorted penta-gonal-bipyramidal. In the crystal structure the uranyl dimers are connected to each other by hydrogen-bonding interactions [O⋯Cl = 3.23 (1) Å].