Langbeinite, structure type

For instance, the structural chemical approach was used to elaborate such crystalline materials as ceramics for immobilization of actinides and other dangerous elements and isotopes present in radioactive waste. The approach was efficient in modelling new lanthanide phosphates of framework NZP-type structure [94, 95] and of the langbeinite structure type [97-101]. 

Fig. 11 shows the structure of K2PrZr(P04)3 that belongs to the langbeinite structure type [99], The Pr atoms are sixfold coordinated. The octahedral sites of the framework are occupied by Pr and Zr in different proportions. 

The compositions of new phosphates with langbeinite structure type with 9-coordinated lanthanide ions have been proposed in [103, 104], The phosphates with composition Ai 5Lno,5[Fe2(P04)3] with A = K, Rb, Cs were s mthesized, and characterized by X-ray diffraction. The predicted cubic modification, space group P2i3 has been confirmed. This prediction seems to be promising for the actinide phosphate as well. 

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