Uranyl Phosphonates with Multiple Uranyl Coordination Geometries and Low Temperature Phase Transition
Lanhua Chen, Yugang Zhang, Zhehui Weng, Zhiyong Liu, Jiarong Zhang, Yaxing Wang, Shuao Wang
Abstract
Main observation and conclusion Two new uranium(VI) phosphonate compounds, namely K 8 [N(C 2 H 5 ) 4 ] 2 (UO 2 ) 17 (H 2 O) 4 [CH 2 (PO 3 ) 2 ] 8 [CH 2 (PO 3 )(PO 3 H)] 4 ‧16(H 2 O) (1) and [N(C 2 H 5 ) 4 ] 4 (H 3 O) 2 (UO 2 ) 10 [CH 2 (PO 3 ) 2 ] 5 [CH 2 (PO 3 )(PO 3 H)] 2 ‧10H 2 O (2), have been synthesized under mild hydro/solvothermal condition. The structural analysis of the two compounds reveals that they both contain all three typical coordination geometries of the U(VI) ions, including UO 6 tetragonal, UO 7 pentagonal, and UO 8 hexagonal bipyramids. Moreover, compound 1 displays a temperature‐induced single crystal to single crystal phase transformation as confirmed by the Single‐crystal X‐ray diffraction data collected at different temperatures. Temperature‐dependent fluorescence spectra presented herein illustrate the perturbation of the electronic structure of uranyl centers.