Barats-Damatov Delina, Shimon Linda J W, Feldman Yishay, Bendikov Tatyana, Neumann Ronny
Department of Organic Chemistry, Weizmann Institute of Science , Rehovot 76100, Israel.
Inorg Chem. 2015 Jan 20;54(2):628-34. doi: 10.1021/ic502541b. Epub 2015 Jan 7.
The crystal packing and secondary structure of H5PV2Mo12O40 was followed by careful X-ray diffraction studies that revealed four unique structures and three solid phase transitions at temperatures between 25 and 55 °C, with loss of solvated water and concomitant contraction of the volume and increase of the packing density. Above 60 °C H5PV2Mo12O40 becomes amorphous and then anhydrous although the polyoxometalate cluster is stable indefinitely up to 300 °C. Above this temperature, combined IR, Raman, XRD, and XPS measurements show the decomposition of H5PV2Mo12O40 to crystalline MoO3 and probably amorphous vanadium oxide and vanadylphosphate, the latter appearing to cover the surface of MoO3. Importantly, H5PV2Mo12O40 can be easily recovered by dissolution in water at 80 °C.
通过仔细的X射线衍射研究追踪了H5PV2Mo12O40的晶体堆积和二级结构，该研究揭示了四种独特结构以及在25至55°C之间的三个固相转变，伴随有溶剂化水的损失以及体积的收缩和堆积密度的增加。60°C以上，H5PV2Mo12O40变为无定形然后无水，尽管多金属氧酸盐簇在高达300°C时可无限期稳定。高于此温度，红外光谱、拉曼光谱、X射线衍射和X射线光电子能谱的综合测量表明H5PV2Mo12O40分解为结晶MoO3以及可能的无定形氧化钒和钒磷酸酯，后者似乎覆盖在MoO3表面。重要的是，H5PV2Mo12O40可通过在80°C的水中溶解而轻松回收。
