On account of their potential possibility of being used as an ion exchanger the diaryliodine(Ⅲ) salts have attracted our attention.A lot of scientific reports concerning these compounds have been found in literature, but had been hardly touching the thought of the possibility.Some of their basic physico-chemical characteristics are still not reported. In this paper we have studied the effect of water in the iodoniumforming reaction with(IO)2SO4.It has been shown that the overoxidization will be slighter and the productive rate of iodonium salts will be higher when the ratio H2SO4:H2O (in moles) equals approximately 2.7:1.The experiment shows that chloroform and 1, 2-dichloroethane as well as tetrachloromathane have no apparent influence for the iodonium forming reaction and the resulting productive rate. At the same time we synthesized thirty-five species of simple iodinium halides and determined their solubilities in water.The experimental results have shown that the halides get the more deeply colour and the solubilities of the halides apparently decrease in the series of Cl^--Br^--I^- and hydrocarbon-halgen-oxygroup substituted group at the benzen cycle. All of these phenomena reflect the change of chemical bond between R2I^+-X-and may be a useful indication in the synthesis of such a kind of ion exchanger.