Crystal and molecular structure of [Tc(CO)(4)I]

Crystal and molecular structure of dimeric technetium tetracarbonyl iodide [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 parameters 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 structure consists of individual [Tc(CO)(4)I](2) molecules, The Tc-C bonds for the CO groups located trans to each other are longer by 0.09 Angstrom than for the CO groups located trans to the halogen atom, which 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.