The stoichiometry and rate constants for the reaction of triphenylphosphite and triphenylphosphine with ozone were measured at several temperatures. The rate was first order in each reactant, with k = (3f 1) x lo4 and ( 5 f 2 ) x lo3 M -' s-' , respectively, for the reaction of ozone with triphenylphosphine and triphenylphosphite (2,4-dimethylhexane, -9 0 ) . The reaction of ozone with triphenylphosphite has a low activation energy in carbon tetrachloride. The stoichiometry was 1:l for both compounds under these conditions. La stoechiomCtrie et les constantes de vitesse de la reaction entre le triphCnylphosphite et la triphinylphosphine avec I'ozone ont Bte mesurees a diverses temptratures. La vitesse est du premier ordre pour chaque reactant avec k = ( 3 i 1) x loJ et ( 5 2 2) x lo3 M -' s-' respectivement pour la triphCny1-phosphine et le triphCnylphosphite (dimithyl-2,4-hexane, -90"). La reaction de I.ozone sur le triphinylphosphite possede une faible energie d'activation dans le tCtrachlorure de carbone. La stoechiometrie est de 1 :1 pour les deux composes dans ces conditions.[Traduit par le journal]Can.