Abstract: Bridged halonium ions were observed to arise on ionization of 1, Zdihaloethanes, 1, 2-dihalopropanes, and 2, 3-dihalobutanes when the participating atom is iodine or bromine. Starting from erythro-or threo-2-bromo-3-fluorobutane, the same mixture of cis-and trans-dimethylethylenebromonium ions was obtained, but from the corresponding iodides, stereospecific formation of the trans-and cis-l, 2-dimethylethyleneiodonium ions, ...
