CRYSTAL AND MOLECULAR-STRUCTURE OF TETRAMERIC [TC(CO)(3)CL](4)

A single-crystal x-ray structure analysis of[Tc(CO)(3)Cl](4) is perfor med. The crystals belong to the cubic system, a = 10.322(3) Angstrom, space group I $($) over bar$$ 43m, Z = 2, d(calc) = 2.63 g/cm(3). The crystal lattice is constructed of isolated tetrameric [Tc(CO)(3)Cl](4) with a cubane-like structure. The Tc(CO)(3) fragments are banded to e ach other through CI bridges with practically no metal-metal interacti on. The total energy and bond multiplicity for [Tc(CO)(3)Cl](4) and th e hypothetical related complexes [Tc(CO)(3)H](4), [Tc(CO)(3)](4+)(4), and Tc-4(4+) with different complex geometric parameters are calculate d by the extended Huckel method.