Preliminary structural data for the crystals of two technetium compounds with complex metal-metal bond systems

The crystal structure of ((H/sub 2/O)/sub 3/H/sub 3/O)/sub 2/-(Tc/sub 6/(Br, OH)/sub 6/Br/sub 6/) (I) and ((CH/sub 3/)/sub 4/N)/sub 3/ (Tc/sub 6/Cl/sub 14/) (II) were studied by x-ray diffraction. Monoclinic crystals of I with space group P2/sub 1//c had a = 9.258(4), b = 9.211(3) and c = 17.437(7) Anstrom, beta = 101.09(3)/sup 0/, and Z = 2. 1220 independent nonzero reflections were obtained. Orthorhombic crystals of II with space group Pcmn had a = 11.583(2), b = 13.527(c), and c = 24.387(3) Angstrom, Z = 4. A total of 2120 independent nonzero reflections were obtained. The study of I was complicated by the disordered arrangement of the 4 bromine atoms. A subsequent study was performed by consecutive refinement, in which the positional multiplicities and thermal parameters of the bromine atoms were refined independently and the other parameters were fixed. Subsequent anisotropic refinement of the structure reduced the reliability factor to 0.055. The structure of II was solved by the heavy atom method and subsequent refinement of the electron density distribution. The coordinates and isotropic thermal oscillation coefficients were refined by least square fit method. 15 references.