A series of divalent transition metal phosphonates containing hydrogen-bonded layers of phosphonate anions, namely [M(phen)(3)].C6H5PO3.11H(2)O [M=Co(1), Ni(2), Cu(3)] and [Cd(phen)(3)].C6H5PO3H.Cl.7H(2)O (4) have been synthesized, structurally characterized by single-crystal X-ray diffraction method. These compounds all crystallize in the triclinic system, space group P-1. The lattice parameters are a = 12.1646(5), b = 12.4155(6), c = 15.4117(10)Angstrom, alpha = 78.216(2), beta = 79.735(3), gamma = 77.8380(3)degrees, V=2205.1(2)Angstrom(3), Z = 2 for 1; a = 12.097(2), b = 12.606(3), c = 15.742(3)Angstrom, alpha = 76.66(3), beta = 80.04(3), gamma = 77.75(3)degrees, V = 2263.4(8) Angstrom(3), Z 2 for 2; a = 12.058(2), b = 12.518(3), c = 15.781(3) Angstrom, alpha = 77.77(3), beta = 80.02(3), gamma = 77.91(3)degrees, V = 2255.5(8) Angstrom(3), Z 2 for 3 and a = 12.47680(10), b = 12.6693(2), c = 16.1504(3) Angstrom, alpha = 82.600(1), beta = 71.122(1), gamma = 77.355(1)degrees, V = 2352.37(6) Angstrom(3), Z = 2 for 4. All structures are refined by full-matrix least-squares methods [for 1, R1 = 0.0602 using 6458 independent reflections with I>2sigma(I); for 2, R1 = 0.0632 using 4657 independent reflections with I>2sigma(I); for 3, R1 = 0.0634 using 6221 independent reflections with I>2sigma(I); for 4, R1 = 0.0400 using 7930 independent reflections with I>2sigma(I)]. In the crystal structures, the phenylphosphonate anions and water molecules are hydrogen-bonded to form layers, and there exist the cationic species [M(phen)(3)](2+) between the adjacent layers of anions and water. Luminescence, thermal analysis as well as IR spectroscopic studies are also presented. (C) 2003 Elsevier Science (USA). All rights reserved.