Hydrothermal synthesis, structure and thermal stability of diamine templated layered uranyl-vanadates

Murielle Rivenet (1) , Nicolas Vigier (1) , Pascal Roussel (1) , Francis Abraham (1)

1 UCCS - Unité de Catalyse et Chimie du Solide - UMR 8181

Six new layered uranyl vanadates (NH4)2[(UO2)2V2O8] (1), (H2EN)[(UO2)2V2O8] (2), (H2DAP)[(UO2)2V2O8] (3), (H2PIP)[(UO2)2(VO4)2].0,8H2O (4), (H2DMPIP)[(UO2)2V2O8] (5), (H2DABCO)[(UO2)2(VO4)2] (6) were prepared from mild-hydrothermal reactions using 1,2-ethylenediamine (EN); 1,3-diaminopropane (DAP); piperazine (PIP); 1-methylpiperazine (MPIP); 1,4-diazabicyclo[2,2,2]octane (DABCO). The structures of 1, 4, 5 and 6 were solved using single-crystal X-ray diffraction data while the structural models of 2 and 3 were established from powder X-ray diffraction data. In compounds 1, 2, 3 and 5, the uranyl-vanadate layers are built from dimers of edge-shared UO7 pentagonal bipyramids and dimers of edge-shared VO5 square pyramids further connected through edge-sharing. In 1 and 3, the layers are identical to that occurring in the carnotite group of uranyl-vanadates. In 2 and 5, the V2O8 dimers differ in orientation leading to a new type of layer. The layers of compound 4 and 6 are built from chains of edge-shared UO7 pentagonal bipyramids connected by VO4 tetrahedra and are of uranophane-type anion topology. For the six compounds, the ammonium or organoammonium cation resides in the space between the inorganic layers.

Domaines: Chimie inorganique

Murielle Rivenet, Nicolas Vigier, Pascal Roussel, Francis Abraham. Hydrothermal synthesis, structure and thermal stability of diamine templated layered uranyl-vanadates. Journal of Solid State Chemistry, 2007, 180, pp.722-733. ⟨10.1016/j.jssc.2006.11.034⟩. ⟨hal-00187339⟩