TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Process: The titanium oxide can be produced by dehalogenating titanium oxide using dry halogenation method involving heating the titanium oxide to 200-500 degrees C, or heating a steam-containing gas to 200-1000 degrees C and contacting it with the titanium oxide. It can also be produced by wet dechlorination method in which titanium oxide is suspended in water and chlorine that is transferred to a liquid phase is discharged outside the resultant suspension; and separating chlorine by ultrafiltration membrane, reverse osmosis membrane, or filter process.Preferred Condition: The residence time of the titanium halogenide-containing gas and the oxidative gas in the reactor is at most 0.1 second. Each halogenide-containing gas and the oxidative gas is preliminary heated at 600-1100 degrees C before being introduced into the reactor. The reaction is performed using a raw material gas mixture containing titanium halogenide and an inert gas at 1:0.1-20 mol, and an oxidative gas at 1-30 mol per 1 mol of the titanium halogenide.When an aqueous suspension containing titanium oxide at 1 mass% is allowed to stand at 20 degrees C for 30 minutes, the amount halogen that is transferred from the titanium oxide to a liquid phase is preferably at least 90 mass% based on the entire amount of the halogen in the titanium oxide.Preferred Components: The oxidative gas is an oxygen gas containing water steam. It contains steam at least 0.1 mol per 1 mol of an oxygen gas. The titanium halogenide is titanium tetrachloride. The steam-containing gas is air-containing steam in an amount of at least 0.1 vol.%.Preferred Composition: The mass ratio of steam to titanium oxide is at least 0.01. The titanium oxide comprises iron, aluminum, silicon, and sulfur each at less than 100 ppm.Preferred Property: The titanium oxide comprises at least 90% anatase or at least 90% brookite. EXAMPLE - A diluted titanium tetrachloride gas and oxidative gas were introduced into a reaction tube. Cooling air was introduced into the reaction tube operating at 800-1100 degrees C such that the residence time was 0.1 seconds. The resultant ultrafine particulate titanium oxide powder was collected using polytetrafluoroethylene-made bag filter.    The titanium oxide powder was made to flow through a heating furnace, and subjected to dechlorination at conditions consisted of a mass ratio of water to titanium oxide of 0.02 and heating temperature of 450.    The dechlorinated titanium oxide had a BET specific surface area of 22 m2/g, a rutile content of 1%, a water-extracted chlorine content of 900 mass ppm, and a total chlorine content of 1000 mass ppm.