Abstract. M r = 840.8, orthorhombic, Ccca, a = 11.620(2), b=15.847(2), c=17-245(4)A, V= 3175 (1)/k 3, Z = 4, D m = 1.7 (1) (1,2-dichloroethane/ 1,2-dibromoethane), D x = 1.759 Mg m -3, ~.(Mo K~t) = 0.7107,&, g=ll.88mm -l, F(000)=1624, T= 298K, final R =0.058 for 1589 unique observed reflections. Cd is octahedrally coordinated with the N atoms of four pyridine molecules and two I-ions in trans positions at average distances of 2.411 (7) and 2.9693 (7)A, respectively. The crystal structure consists of layers perpendicular to e, built up of transCdI2(py)4 units linked together by van der Waals interactions between the ligating pyridine(py) molecules. The guest pyridine molecules are enclathrated in the cavities formed between the layers.
Introduction. A series of complexes of the type MP4X 2(where M is a divalent transition metal, P a pyridine derivative and X a halide or thiocyanate ion) form clathrate compounds with various guest molecules (Schaeffer, Dorsey, Skinner & Christian, 1957).There has been no report on cadmium-pyridine complexes except for the early work of Paulus (1969) on Cd(py)2C12 which possesses a pseudooctahedral polymeric structure with bridging halide ligands. The crystal structure of the new clathrate compound, diiodotetrakis(pyridine)cadmium(II), which contains enclathrated pyridine guest molecules, has been determined.
