氟碳铈钡矿Ba_3Ce_2（CO_3）_5F_2晶体结构重测

STRUCTURE REDETERMINATION OF CEBAITE-(Ce),Ba_3Ce_2(CO_3)_5F_2

氟碳铈钡矿Ｂａ３Ｃｅ２（ＣＯ３）５Ｆ２的晶体结构原先被描述为Ｃｍ和Ｐ２空间群，经单晶Ｘ射线衍射方法重测为Ｃ２／ｍ空间群；采用２３３９个独立反射，１５１个可变参数，Ｒ＝０．０３４，Ｒｗ＝０．０５。经检测，未发现明显违反Ｃ心布拉维格子的反射；误差允许范围内位移椭球体与所定空间群相容。结构中的原子排列与化合物Ｂａ３Ｌａ２（ＣＯ３）５Ｆ２相似，可被描述为平行于（１０２）层间有序结构，层与层之间通过碳酸根相联结。

he crystal structure of Cebaite-(Ce), Ba3Ce2(CO3)5F2,was previously described in space groups Cm and P2. Using single crystal X-ray diffraction it was refined in C2/m,2339 unique reflections, 151 variables, R = 0. 034, Rw = 0. 05. Reflections definitely violating the C-centered Brayals lattice were not detected; and displacement ellipsoids are compatible with the space group chosen within the limits of accuracy. The atomic arrangement compares very closely to that of synthetic Ba3La2(CO3 )5F2. It can be described as an intra - layer-ordered structure with layers parallel (102) that are interconnected by carbonate groups.