Polynuclear Iron(II) and Iron(III) derivatives of 1-Aminoethylidenediphosphonic acid (AEDP, H₄L¹), Alpha-Amino benzylidene diphosphonic acid (ABDP, H₄L²), 1-Amino-2-carboxyethane-1,1-diphosphonic acid (ACEDP, H₅L³), 1,3 Diaminopropane-1,1,3,3-tetraphosphonic acid (DAPTP, H₈L⁴), Diethylene triamine -N,N,N',N",N"-penta ( methylene phosphonic) acid (DETAPMPO, H₁₀L⁵), and Diethylene triamine -N,N"-bis (dimethyl methylene phosphonic) acid (DETBDMPO, H₄L⁶) have been prepared in aqueous medium. The general formula of Iron (II) derivatives from elemental analysis is Fe₂L.XH₂O (in case of AEDP, ABDP, DETBDMPO), Fe₅L₂.XH₂O (in case of ACEDP) Fe₂L.XH₂O, Fe₃H₄L₂.XH₂O (in case of DAPTP), Fe₅L.XH₂O (in case of DETAPMPO). The general formula of Iron (III) derivatives from elemental analysis is Fe₄(OH)₄.L.XH₂O (in case of AEDP, ABDP, DETBDMPO ), Fe₅L(OH) (in case of DAPTP) Fe₅L(OH)₅.H₂O(in case of DETAPMPO). The electronic spectra of Iron (II) complexes have shown them to have octahedral geometry. Antiferromagnetism has been inferred from magnetic moment data. Infrared spectral studies were carried out to determine coordination sites.