The optical characteristics, solubility, and decomposition kinetics of ozone in polar (acetonitrile, CH 3 CN) and nonpolar (carbon tetrachloride, CCl 4 ) liquids in the temperature range 233.15-295.15 K were studied. The rate constants of the O 3 decomposition at 295.15 K in CH 3 CN and CCl 4 are 3.3 × 10 À 5 and 5.0 × 10 À 5 s À 1 , respectively. At low temperatures, ozone solu-tions are practically stable. The solubility coefficients at 295.15 K are 2.6 in CH 3 CN and 2.9 in CCl 4 ; at 233.15 K, they increase to approximately 7.0. Thus, these two liquids have a set of properties making them optimum for studying the ozonolysis in polar and nonpolar media.