Two new orotic acid complexes of cadmium(II) with protonated monodentate ethylenediamine and 1, 10-phenanthroline were synthesized and characterized by X-ray diffraction techniques. trans-[Cd(HOr)(2)(enH)(2)]center dot 2H(2)O (1) (enH = ethylenediammonium) crystallizes in the triclinic system, space group P (1) over bar, and the Cd(II) ion exhibits a distorted octahedral coordination by bis(bidentate) orotate anions and two protonated monodentate ethylenediamine ligands. The individual molecules of I are held together by N-H center dot center dot center dot O and O-H center dot center dot center dot O hydrogen bonds, forming a three-dimensional network. The supramolecular compound cis-[Cd(H2O)(2)(phen)(2)](H(2)Or)(2 center dot)2H(2)O (2) (phen = 1, 1 0-phenanthroline) crystallizes in the monoclinic system, space group C2/c and the Cd(II) ion is coordinated by two symmetry related aqua ligands together with a pair of symmetry related bidentate 1, 10-phenanthroline molecules, and exhibits a distorted octahedral coordination. The unique orotate anion in the asymmetric unit has a single negative charge. The coordinated water molecules link the orotate ions to the metal complex via O-H center dot center dot center dot O hydrogen bonds. Each uncoordinated water molecule is hydrogen bonded to orotate ions through O-H center dot center dot center dot O hydrogen bonds. Thus, an extensive network of hydrogen bonds stabilizes the crystal structure and forms an infinitive three dimensional lattice. The IR spectrum and thermal analysis of I is described. The decomposition reaction take places in the temperature range 20-1000 degrees C in static air atmosphere. (c) 2007 Elsevier Ltd. All rights reserved.