Diaqua-bis-(dihydrogen 3-aza-niumyl-1-hy-droxy-propyl-idene-1,1-di-phos-phon-ato-κO,O')cobalt(II).

The asymmetric unit of title compound, [Co(C(3)H(10)NO(7)P(2))(2)(H(2)O)(2)], contains one half-mol-ecule of the complex. The Co(II) atom is located on an inversion centre and displays a distorted octa-hedral coordination geometry defined by four O atoms of two 3-aza-niumyl-1-hy-droxy-propyl-idene-1,1-bis-phospho-nato ligands in the equatorial plane and two water mol-ecules located in axial positions. The ligand mol-ecules, which exist in a zwitterionic state, form two six-membered chelate rings with chair conformations. In the crystal, mol-ecules are inter-linked by O-H⋯O and N-H⋯O hydrogen bonds, forming a three-dimensional supra-molecular structure.