CRYSTAL AND MOLECULAR-STRUCTURE OF TC(CO)(5)I

Crystal and molecular structure of technetium pentacarbonyl iodide Tc( CO)(5)I was studied by single crystal X-ray diffraction. Tc(CO)(5)I cr ystallizes in the rhombic system; the cell parameters are a = 7.621(3) , b = 11.048(3), c = 10.812(4) Angstrom, V = 910.3(9) Angstrom(3), spa ce group Cmcm, Z = 4, d(calc) = 2.663 g cm(-3), mu(MoKalpha) = 48.8 cm (-1). The crystal structure consists of individual Tc(CO)(5)I molecule s. The equatorial Tc-C bonds are longer than the axial bonds by 0.08 A ngstrom, which is caused by the trans effect of carbonyl groups. The c ompound is isostructural with Mn(CO)(5)I but not isostructural with Re (CO)(5)Cl and Re(CO)(5)Br. The main difference is in the mutual orient ation of molecules in the pseudohexagonal lattice.