A disordered cerium(IV) phosphate with a tunnel structure,K4CeZr(PO4)4

Tetra­potassium cerium(IV) zirconium tetra­kis­(mono­phos­phate) crystallizes in the tetra­gonal system (space group I4₁/amd). A complex disorder in K₄CeZr(PO₄)₄ involves the mixing of Ce and Zr atoms on a single site with m2 symmetry and the splitting of P‐ and O‐atom positions, equivalent to a rotation of the phosphate groups, to yield eight‐ and sixfold coordination environments around Ce and Zr, respectively. The K atoms are located in tunnels running parallel to the a and b axes.