catena -Poly[oxidanium [tris{μ-[amino(iminio)methyl]phosphonato}zincate(II)]].

The crystal structure of the anionic zinc-[amino-(iminio)meth-yl]phospho-nate one-dimensional coordination polymer, Zn-AIMP, is reported; the negative charge is balanced by an oxidanium cation (H 3 O + ) to give the composition {(H 3 O)[Zn(CH 4 N 2 PO 3 ) 3 ]} n . The building unit of the coordination polymer comprises a divalent Zn 2+ cation (site symmetry ..) and three [amino(iminio)meth-yl]phospho-nate mono-anionic ligands (point group symmetry m ). The AIMP ligand exists in a zwitterionic form with a total charge -1 as the phospho-nate is fully deprotonated (-PO 3 2- ), while the amino-(iminio)methyl moiety is protonated (H 2 N-C-NH 2 + ).