LAUSR

Abstract Three novel uranyl selenate and sulfate oxysalts templated by protonated azetidine molecules, [ Az H] + , and its ring-opened counterpart 1-azetidinepropanamine, [ Az H(CH 2 ) 3 NH 3 ] 2+ , have been prepared and studied by X-ray structural analysis. Conformations of azetidinium cations were analysed by means of infrared vibrational assignments supported by the DFT calculations. Crystallization of [ Az H] 2 [(UO 2 ) 2 (SeO 4 ) 3 (H 2 O)] ( I ) from highly acidic solutions suggests that low pH does not necessarily result in the opening of azetidine ring. [ Az H(CH 2 ) 3 NH 3 ][(UO 2 ) 2 (SeO 4 ) 3 (H 2 O)](H 2 O) ( II ) and [ Az H(CH 2 ) 3 NH 3 ](H 5 O 2 )[(UO 2 ) 2 (SO 4 ) 3 (HSO 4 )] ( III ) are the first structurally characterized crystalline compounds bearing isolated ring-opened azetidine moiety.