COMPOSITION BASED ON CERIUM AND ZIRCONIUM OXIDES HAVING A SPECIFIC SURFACE WHICH IS STABLE BETWEEN 9

The inventive composition, according to a first embodiment, consists essentially of a cerium oxide and a zirconium oxide. According to a second embodiment, said composition is based on cerium oxide, zirconium oxide and at least one rare earth oxide other than cerium. After a first 4-hour period of calcination at 900 °C followed by a second 10-hour period of at 1000 °C, the specific surface variation thereof is 20 % maximum in the first embodiment and 15 % maximum in the second embodiment. The inventive composition can be used as a catalyst, i.e. in the treatment of waste gases from internal combustion engines.