of noble gas compounds. Autoionization Many inorganic solvents participate in autoionization reactions. In the solvent system definition of acids and bases, autoionization of solvents affords the equivalent to acids and bases. Relevant autoionizations: 2BrF3 BrF2+ + BrF4− N2O4 ⇌ NO+ (nitrosonium) + NO3− (nitrate) 2SbCl3 ⇌ SbCl2+ + SbCl4− 2POCl3 ⇌ POCl2+ + POCl4− According to the solvent-system definition, acids are the compounds that increase the concentration of the solvonium (positive) ions, and bases are the compounds that result in the increase of the solvate (negative) ions, where solvonium and solvate are the ions found in the pure solvent in equilibrium with its neutral molecules: The solvent SO2 is relatively uncomplicated, it does not autoionize. See also Nonaqueous titration Protic solvent References External links Solvents Solutions