Compounds containing the dioxychloronium cation, [ClO 2 ] + , were obtained from reactions of ClF 3 with various oxides such as TiO 2 , MoO 3 , Re 2 O 7 , SnO, P 2 O 5 , As 2 O 5 , and Nb metal, as the latter contained oxide as an impurity. Partial hydrolysis of [ClF 2 ] [IrF 6 ] led to the formation of [ClO 2 ][IrF 6 ]. The crystal structures of the compounds were determined by single-crystal X-ray diffraction, which showed that depending on the starting material [ClO 2 ] + salts with the fluoridometallate anions [TiF 3/2 F 3/