SYNTHESIS AND CRYSTAL-STRUCTURE OF (TECL3 )(2)MOCL6 AND BETA-(TECL3)(2)RECL6

Single crystals of (TeCl3)(2)MoCl6 and beta-(TeCl3)(2)ReCl6 are obtain ed by the reactions of TeCl4 with MoCl4 at 195 degrees C and of TeCl4/ Te with ReCl5 at 150 degrees C, respectively The compounds form dark-r ed moisture sensitive crystals. The crystal structure determinations s how, that both crystallize isotypically (rhombohedral, space group <R( 3)over bar>. (TeCl3)(2)MoCl6: a = 1116,9(1). c = 3539,5(5) pm. 1966 un ique reflections for 69 parameters, final R = 0.058; beta-(TeCl3)(2)Re Cl6: a = 1113,3(3), c = 3546(2) pm. 1653 unique reflections for 70 par ameters, final R = 0.034). The structures consist of octahedral MCl(6) (2-) anions (with M = Mo,Re) and pyramidal TeCl3+ cations. The ions ar e interconnected through long Te-Cl bridges (291,1 - 295,6 pm) to give distorted TeCl6 octahedra. MCl(6) and TeCl6 units are connected via e dges and corners, resulting in a complex layer structure with layers p arallel to the ab-plane. In the previously reported alpha-form of (TeC l3)(2)ReCl6, only connections via corners are observed.