The iron phosphate CaFe(3)(PO(4))(3)O.

A new iron phosphate, calcium triiron(III) tris-(phosphate) oxide, CaFe(3)(PO(4))(3)O, has been isolated and shown to exhibit a three-dimensional structure built by FeO(6) octa-hedra, FeO(5) trigonal bipyramids and PO(4) tetra-hedra. The FeO(x) (x = 5, 6) polyhedra are linked through common corners and edges, forming [Fe(6)O(28)](∞) chains with branches running along [010]. Adjacent chains are connected by the phosphate groups via common corners and edges, giving rise to a three-dimensional framework analogous to those of the previously reported SrFe(3)(PO(4))(3)O and Bi(0.4)Fe(3)(PO(4))(3)O structures, in which the Ca(2+) cations occupy a single symmetry non-equivalent cavity.