STUDIES OF POLYHALIDES .20. PREPARATION AND CRYSTAL-STRUCTURE OF TETRA(METHYLTRIPHENYLPHOSPHONIUM)DOCOSAIODIDE (MEPH(3)P)(4)I-22

The new compound (MePh(3)P)(4)I-22 has been prepared by the reaction of Ph(3)MePI with iodine in a mixture of methanol and dichloromethane. It crystallizes in the triclinic space group P (1) over bar with a = 1018.4(3), b = 1333.0(4), c = 2042.9(6) pm, alpha = 55.56(2), beta = 78.05(2), gamma = 76.03(2)degrees and Z = 1. The crystal structure has been refined to R(F) = 0.0487 for 5525 reflections. It may be described as a layer-like packing of cations [CH3(C6H5)(3)P](+) and anions I-22(4-) divided in one I-12(2-) and two I-5(-) groups. The central I-12(2-) anion with point symmetry C-i consisting of two L-shaped pentaiodide groups and a bridging iodine molecule is completed by two further end-on bonded pentaiodide ions with a rather short distance of 366.7(2) pm to the weakly bonded and nearly isolated docosaiodide ion.