Thermodynamic and kinetic characteristics of cerium(IV) malonate complex formed in the first stage of cerium(IV) oxidation by malonic acid H(2)Mal are studied using a spectrophotometer, a photometer, and a pH-meter at a ionic strength of I = 2 in the pH region of 0.3-1.6 in a sulfuric acid medium at a temperature of 296.8 K. Its composition is found to be CeOHMal(+). The form of organic ligand is Mal(2-); the thermodynamic parameters of its formation and kinetic parameters of its intramolecular redox decomposition are determined. The most likely scheme of the initial stages of redox proceeding in the Ce4+ SO42- H-2 Mal system is discussed, and a quantitative model of it is proposed.