Commercial bis-(4-bromophenyl)-ether, [BrC6H4](2)-O, has been used to prepare 4-[4'-(diethoxyphosphoryl)phenoxy]phenyl-phosphonic acid diethyl ester, [(CH3CH2)(2)O3P-C6H4](2)-O, (I) following a slight modification of the Michaelis-Arbuzov reaction. The acid hydrolysis of I gave 4-(4'-phosphonophenoxy)phenyl phosphonic acid, [H2O3P-C6H4](2)-O (II), and both compounds have been characterized by H-1 NMR and C-13 NMR. The crystal structure of II has been determined by single-crystal X-ray diffraction. II crystallizes in an orthorhombic unit cell, space group Pbcn, with a = 7.822(3) Angstrom, b = 5.821(2) Angstrom, c = 28.982(9) Angstrom, and V = 1319.7(7) Angstrom(3). The final R factor was R1 = 0.0614. The structure is layered, being held together through a hydrogen bonding network. II has been used as precursor in the syntheses of new metal (Mn, Fe, Co, Ni, Cu, and Zn) bisphosphonates. The syntheses were carried out using a fixed metal/bisphosphonic acid molar ratio of 2.1:1 and the influence of the pH in the reactions has been studied. Nine new compounds have been isolated: Mn-2(O3PC6H4OC6H4PO3)(.)1.5H(2)O (III), Mn-5(OH)(2)(O3PC6H4OC6H4PO3)(2)(.)2H(2)O (IV), Fe(HO3PC6H4OC6H4PO3)(.)0.5H(2)O M, CO2(O3PC6H4OC6H4PO3)(.)2H(2)O (VI), Ni-2(O3PC6H4OC6H4PO3)(.)3H(2)O (VII), Ni-2(O3PC6H4OC6H4PO3)(.)2H(2)O (VIII), Cu-2(O3PC6H4OC6H4PO3) (IX), Zn-2(O3PC6H4OC6H4PO3) (X), and Zn(HO3PC6H4OC6H4PO3H) (XI). Compound IX crystallizes in an orthorhombic unit cell, space group Pbcn, and unit cell parameters a = 8.1012(5) Angstrom, b = 5.3109(3) Angstrom, c = 29.2595(5) Angstrom, and V = 1258.8(1) Angstrom(3). Its structure has been solved by ab initio powder diffraction and refined by the Rietveld method to R-F = 0.042. IX has a pillared layer framework with highly distorted CuO5 groups sharing edges to give isolated dimers. XI was indexed in a monoclinic unit cell, space group P112(1), with parameters a = 9.4991 (9) Angstrom, b = 5.0445(5) Angstrom, c = 29.131(2) Angstrom, gamma = 91.945(7)degrees, and V = 1395.1(3) Angstrom(3). Its structure has been refined by the Rietveld method, R-F = 0.054, since it is isostructural with the known compound, Zn[HO3P(C6H4)(2)PO3H]. All solids were also characterized by thermal analysis and IR and UV-Vis spectroscopies.