CRYSTAL AND MOLECULAR-STRUCTURE OF [TC(CO)(4)I]

Crystal and molecular structure of dimeric technetium tetracarbonyl io dide [Tc(CO)(4)I](2) was studied by single crystal X-ray diffraction. [Tc(CO)(4)I](2) crystallizes in the monoclynic system; the cell parame ters are a = 10.048(2), b = 12.319(5), c = 13.200(3) Angstrom, beta = 108.04(2)degrees, V = 1553.6(1.5) Angstrom(3), space group P2(1)/c, Z = 4, d(calc) = 2.881 g cm(-3), mu(MoKalpha) = 57 cm(-1). The crystal s tructure consists of individual [Tc(CO)(4)I](2) molecules, The Tc-C bo nds for the CO groups located trans to each other are longer by 0.09 A ngstrom than for the CO groups located trans to the halogen atom, whic h is caused by the trans effect of carbonyl groups. Complexes [M(CO)(4 )X](2) (M = Mn, Tc, and Re; X = Cl, Br, and I) are isostructural.