Gougeon Patrick, Gall Philippe
Sciences Chimiques de Rennes, UMR CNRS No. 6226, Université de Rennes I - INSA Rennes, Avenue du Général Leclerc, 35042 Rennes CEDEX, France.
Acta Crystallogr Sect E Struct Rep Online. 2011 May 1;67(Pt 5):i34-i35. doi: 10.1107/S1600536811015649. Epub 2011 Apr 29.
The structure of hexa-deca-praseodymium henicosa-molybden-um hexa-penta-contaoxide, Pr(16)Mo(21)O(56), is isotypic with other rare earth representatives of formula type RE(16)Mo(21)O(56) (RE = La, Ce, Nd). It is characterized by Mo(10)O(18) (i)O(8) (a) units (where i = inner and a = apical O atoms) containing biocta-hedral Mo(10) clusters and octa-hedral MoO(6) units that share some of their O atoms to form the Mo-O framework. The two independent Mo(10) cluster units are centred at Wyckoff positions 2b and 2c and have point-group symmetry [Formula: see text]. The Mo atom of the MoO(6) unit is likewise situated at an inversion centre (2d). The eight crystallographically different Pr(3+) cations occupy irregular voids in the framework with coordination numbers to the O atoms varying between 8 and 11.
十六镨二十一钼五十六氧化物（Pr(16)Mo(21)O(56)）的结构与通式为RE(16)Mo(21)O(56)（RE = La、Ce、Nd）的其他稀土化合物同型。其特征在于含有双八面体Mo(10)簇和八面体MoO(6)单元的Mo(10)O(18) (i)O(8) (a)单元（其中i = 内部，a = 顶端O原子），这些单元共享部分O原子以形成Mo - O框架。两个独立的Mo(10)簇单元位于Wyckoff位置2b和2c，并具有点群对称性[公式：见原文]。MoO(6)单元的Mo原子同样位于一个对称中心（2d）。八个晶体学上不同的Pr(3+)阳离子占据框架中的不规则空隙，与O原子的配位数在8到11之间变化。
