77Se NMR spectroscopic, DFT MO, and VBT investigations of the reversible dissociation of solid (Se6I2)[AsF6]2.2SO2 in Liquid SO2 to solutions containing 1,4-Se6I2(2+) in equilibrium with Se(n)2+ (n = 4, 8, 10) and seven binary selenium iodine cations: preliminary evidence for 1,1,4,4-Se4Br4(2+) and cyclo-Se7Br+.

The composition of a complex equilibrium mixture formed upon dissolution of (Se(6)I(2))[AsF(6)](2).2SO(2) in SO(2)(l) was studied by (77)Se NMR spectroscopy at -70 degrees C with both natural-abundance and enriched (77)Se-isotope samples (enrichment 92%). Both the natural-abundance and enriched NMR spectra showed the presence of previously known cations 1,4-Se(6)I(2)(2+), SeI(3)(+), 1,1,4,4-Se(4)I(4)(2+), Se(10)(2+), Se(8)(2+), and Se(4)(2+).