Polyiodide complexes of benzophenone (B) with iodine (I) and alkali iodide (MI, M = Na, K, Rb or Cs) have been prepared from methanol for the first time. The crystals of these complexes (abbreviated BIMI) are in the shape of hexagonal prisms with golden luster sides and black cross sections. BIMI complexes exhibit semiconductive behavior from 250 to 310 K with activation energies of 0.6 to 0.8 eV. Under an applied dc field at room temperature, the longitudinal conductivity of BIMI crystals is in the order of 10−6 Scm−1 and does not decrease over a period of half an hour, indicating no ionic conductivity in these complexes. In contrast, significant ionic conductivity is observed for benzophenone complexes grown from chloroform. It is concluded that the solvent molecules play an important role in determining the electrical behavior of the resulting benzophenone complexes. The results of conductivity and resonance Raman spectroscopic studies on the entire methanol series of BIMI complexes suggest that a common conduction pathway is probably provided by the polyiodide chains in this new series of benzophenone complexes.
