Bih Hssain, Bih Lahcen, Manoun Bouchaid, Azrour Mohamed, Lazor Peter, El Ammari Lahcen
Acta Crystallogr Sect E Struct Rep Online. 2010 Feb 20;66(Pt 3):i20-i21. doi: 10.1107/S160053681000601X.
The title compound, (NH(4))(5)Na(7)Mo(5)P(2)O(23)·21H(2)O, was prepared under atmospheric conditions in aqueous solution at room temperature. The structure contains the Mo(5)P(2)O(23) heteropolyoxometallate anion, which has been previously reported a number of times with a variety of differing counter-cations. Each anion is built up of five MoO(6) octa-hedra sharing an edge and forming a ring which is closed by common corners of the terminal octa-hedra. The rings are closed on both sides by two asymmetric PO(4) tetra-hedra, sharing three corners with three MoO(6) octa-hedra. The anions are chiral and the two independent anions in the asymmetric unit were arbitarily chosen with the same chirality, but the centrosymmetric crystal contains both enanti-omers. The structure can alternatively be described as a succession of layers parallel to (101), formed by the Mo(5)P(2)O(23) anions and linked by sodium chains. Water mol-ecules and ammonium ions fill the remaining space and ensure the cohesion through extensive N-H⋯O and O-H⋯O hydrogen bonding.
标题化合物(NH₄)₅Na₇[Mo₅P₂O₂₃]₂·21H₂O是在大气条件下于室温的水溶液中制备的。该结构包含[Mo₅P₂O₂₃]⁶⁻杂多金属氧酸盐阴离子，此前已多次报道其与多种不同的抗衡阳离子形成的化合物。每个阴离子由五个共享一条边的MoO₆八面体构成，并形成一个环，该环由末端八面体的公共角封闭。环的两侧由两个不对称的PO₄四面体封闭，它们与三个MoO₆八面体共享三个角。阴离子具有手性，不对称单元中的两个独立阴离子被任意选择为具有相同的手性，但中心对称的晶体包含两种对映体。该结构也可以描述为由[Mo₅P₂O₂₃]⁶⁻阴离子形成的平行于(101)的一系列层，并由钠链连接。水分子和铵离子填充剩余空间，并通过广泛的N-H⋯O和O-H⋯O氢键确保凝聚。
