Particles of metallic oxide covered with silicon dioxide.

Coated oxide particle, composed of a metal oxide core and a silicon dioxide shell that surrounds the core, characterized in that it shows the absence of an end point in the absorption of dibutyl phthalate, a photo-catalytic activity, determined by oxidation of 2-propanol in acetone, less than 0, 20 or 10- 3 molukg-1umin-1, a BET surface, determined according to DIN 66131, between 5 and 600 m2 / g, a primary particle size between 2 and 100 nm and a secondary particle size between 0.05 and 50 m, and a silicon dioxide shell layer thickness between 0.5 and 25 nm, in which the metal oxides comprise titanium dioxide, zinc oxide, oxide Zirconium, iron oxide, cerium oxide and / or chemical mixtures of these metal oxides with each other, and / or chemical mixtures of these metal oxides with aluminum oxide, and / or chemical mixtures of these metal oxides with silicon dioxide.