STUDIES OF POLYHALIDES .22. ON DIMETHYLDI PHENYLAMMONIUMPOLYIODIDES (ME(2)PH(2)N)I-N WITH N=3,13 3,6, AND 8 - PREPARATION AND CRYSTAL-STRUCTURES OF A TRIIODIDE (ME(2)PH(2)N)I-3, TRIDECAIODIDE (ME(2)PH(2)N)(3)I-13, DODECAIODIDE (ME(2)PH(2)N)(2)I-12, AND HEXADECAIODIDE (ME(2)PH(2)N)(2)I-16/

The new compounds [(CH3)(2)(C6H5)(2)N]I-3, [(CH3)(2)(C6H5)(2)N]I-3(13) , [(CH3)(2)(C6H5)(2)N]I-2(12) and [(CH3)(2)(C6H5)(2)N]I-2(16) have bee n prepared by the reaction of dimethyldiphenylammonium iodide [(CH3)(2 )(C6H5)(2)N]I with iodine I-2 in ethanol. Their crystal structures hav e been determined by single crystal X-ray diffraction methods. The str ucture of the triiodide may be described as a layerlike packing of pai rs of nearly linear symmetric anions and tetraedral cations. The tride caiodide forms zig-zag chains of iodide ions and iodine molecules with the iodide ion also weakly coordinated by two pentaiodide groups. The dodecaiodide is built from two pentaiodide-groups, which are bridged by an iodine molecule and connected with secondary bonds forming doubl e chains. The hexadecaiodide ion forms layers built up from two heptai odide groups and one iodine molecule. Thus the dimethyldiphenylammoniu m cation stabilizes a unique series of polyiodides of extraordinary co mposition and structure.