Orthophosphates of Tetravalent Ce, Th, U, Np, and Pu with the Monazite Structure

Author： Kitaev D. B. Volkov Yu. F. Orlova A. I.

ISSN： 1066-3622

Source： Radiochemistry, Vol.46, Iss.3, 2004-05, pp. : 211-217

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

The problem of development of a ceramic phosphate matrix for solidification of the lanthanideactinide fraction of radioactive wastes is tackled from the crystal-chemical viewpoint. New double orthophosphates of tetravalent f elements (Ce, Th, U, Np, Pu) with alkaline-earth elements and cadmium of the formulas B0.5M₂(PO₄)₃ and B1.5M1.5(PO₄)₃ (B = Mg, Ca, Sr, Ba, Cd; M = Ce, Th, U, Np, Pu) were prepared. The compounds were characterized by X-ray diffraction (including high-temperature measurements) and IR spectroscopy. They crystallize in the monazite structural type (space group P2₁/n). The thermal behavior of the compounds was studied. The unit cell parameters of the phases synthesized were determined. The influence of the cationic composition on the structure formation is analyzed.