Lithium holmium(III) polyphosphate(V), LiHo(PO(3))(4), belongs to the type I of polyphosphates with general formula ALn(PO(3))(4), where A is a monovalent cation and Ln is a trivalent rare earth cation. In the crystal structure, the polyphosphate chains spread along the b-axis direction, with a repeat period of four tetra-hedra and 2(1) inter-nal symmetry. The Li and Ho atoms are both located o...