The structure of cerium orthophosphate, a synthetic analogue of monazite

The crystal structure of CePO4 has been determined by modern X-ray crystallographic techniques. The unit cell is monoclinic (space group P21/n) with a = 6.777(3), b = 6.993(3), c = 6.445(3) A, and β = 103.54(4)0. The final least-squares refinement yielded R = 0.0276, and Rsub(w) = 0.0280. The structure is made up of irregular 9-coordinated cerium atoms linked together by distorted tetrahedral phosphate groups. Comparisons with previous structural determinations of natural monazites are made. A potential application of the lanthanide orthophosphates as a nuclear waste matrix material is briefly discussed. (author)