Novel hexachlorocyclodiphosph(V)azane of sulfaguanidine, H4L, 1,3-[N'-amidino-sulfanilamide]-2,2,2,4,4,4-hexachlorocyclodiphosph(V)azane was prepared and its coordination behaviour towards the transition metal ions Fe(III), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and UO2(11) was studied. The structures of the isolated products are proposed based on elemental analyses, IR, UV-vis, H-1 NMR, mass spectra, reflectance, magnetic susceptibility measurements and thermogravimetric analysis (TGA). The hyperfine interactions in the isolated complex compounds were studied using 14.4keV gamma-ray from radioactive Co-57 (Mossbauer spectroscopy). The data show that the ligand are coordinated to the metal ions via the sulfonamide O and deprotonated NH atoms in an octahedral manner. The H4L ligand forms complexes of the general formulae 1(MXz)(2)(H2L)H2O)(n)] and [(FeSO4)(2) (H4L) (H2O)(4)], where X = NO3 in case Of UO2(II) and Cl in case of Fe(Ill), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II). The molar conductance data show that the complexes are non-electrolytes. The thermal behaviour of the complexes was studied and different thermodynamic parameters were calculated using Coats-Redfern method. Most of the prepared complexes showed high bactericidal activity and some of the complexes show more activity compared with the ligand and standards. (c) 2005 Elsevier B.V. All rights reserved.