On the possibility of realization of monazite and langbeinite structural types in complex americium and plutonium phosphates. Synthesis and X-ray diffraction studies

The existence of phosphates containing Am + Pu with monazite-type structure and of those containing Am + Zr with langbeinite-type structure was substantiated on the basis of the main principles of isomorphism. The compounds were synthesized and examined by X-ray diffraction. Samples of the composition CdAmPu(PO 4 ) 3 crystallized in the monazite structural type. In the sample containing Am + Zr, in which the formation of a langbeinite-type compound was expected by analogy with lanthanides and Zr [isoformula phosphates K 2 LnZr(PO 4 ) 3 , where Ln = Ce-Yb, are known], a mixture of monazite and kosnarite phases was obtained from the chosen reactants under the chosen conditions.