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