Colin J F, Bataille T, Ashbrook S E, Audebrand N, Le Pollès L, Pivan J Y, Le Fur E
Sciences Chimiques de Rennes, UMR 6226, CNRS-Université de Rennes 1-ENSCR, 35042 Rennes Cedex, France.
Inorg Chem. 2006 Jul 24;45(15):6034-40. doi: 10.1021/ic060483t.
The vanadyl oxalatophosphate Na2[(VO)2(HPO4)2C2O4].2H2O has been synthesized by hydrothermal treatment. Its structure has been determined and refined by combining X-ray powder diffraction and solid-state NMR techniques. It crystallizes with monoclinic symmetry in space group P2(1), a = 6.3534(1) A, b = 17.1614(3) A, c = 6.5632(1) A, beta = 106.597(1) degrees . The structure is related to that of (NH4)2[(VO)2(HPO4)2C2O4].5H2O, which was previously reported. The vanadium phosphate framework consists of infinite [(VO)(HPO4)] chains of corner-sharing vanadium octahedra and hydrogenophosphate tetrahedra. The oxalate groups ensure the connection between the chains to form a 2D structure. The sodium ions and the water molecules are located between the anionic [(VO)2(HPO4)2C2O4]2- layers. The thermal decomposition has been studied in situ by temperature-dependent X-ray diffraction and thermogravimetry. It takes place in three stages, where the first two correspond to water removal and the last to the decomposition of the oxalate group and water elimination, leading to the final product NaVOPO4.
草酸氧钒磷酸钠Na2[(VO)2(HPO4)2C2O4].2H2O已通过水热法合成。结合X射线粉末衍射和固态核磁共振技术确定并精修了其结构。它以单斜晶系在空间群P2(1)中结晶，a = 6.3534(1) Å，b = 17.1614(3) Å，c = 6.5632(1) Å，β = 106.597(1)°。该结构与先前报道的(NH4)2[(VO)2(HPO4)2C2O4].5H2O的结构相关。磷酸钒骨架由角共享钒八面体和磷酸氢四面体的无限[(VO)(HPO4)]链组成。草酸基团确保链之间的连接以形成二维结构。钠离子和水分子位于阴离子[(VO)2(HPO4)2C2O4]2-层之间。通过温度依赖的X射线衍射和热重分析对热分解进行了原位研究。它分三个阶段进行，前两个阶段对应于水的去除，最后一个阶段对应于草酸基团的分解和水的消除，最终产物为NaVOPO4。
