TlPO3 and its comparison with isotypic RbPO3 and CsPO3

The crystal structure of thallium(I) catena-polyphosphate, TlPO3, contains a polyphosphate chain extending parallel to [010] with a repeating unit of two phosphate tetra­hedra. The TlI atom is located in-between the polyphosphate chains and is bonded by oxygen atoms in a distorted [6 + 1] coordination in the form of a monocapped prism, with the longest Tl—O bond to the bridging O atom of the polyphosphate chain. A qu­anti­tative structural comparison with isotypic RbPO3 and CsPO3 reveals that the usually pronounced stereoactivity of the 6s2 lone pair at the TlI atom is not apparent in the case of TlPO3.