Facile syntheses of pure uranium halides: UCl4, UBr4 and UI4.

Herein we describe convenient lab scale syntheses of several uranium(iv) halides of high purity by reaction of AlX3 (X = Cl, Br and I) with UO2, which is readily available by reduction of uranyl salts like UO2(NO3)2·6H2O. UCl4, UBr4, and UI4 are obtained in the form of aggregates of large single crystals. Their identities and purity were checked by powder X-ray diffraction, IR spectroscopy and elemental analysis. The syntheses introduced here avoid the need for pure metallic uranium and are based on more readily available starting materials, UO2, which does not even have to be pure, and the respective aluminium halide. Chemical vapor transport (CVT) is applied in situ for purification of the products.