Amorphous silica-titania composite oxide powder, resin composition, liquid dispersion, and method for producing silica-coated silica-titania composite oxide powder

Amorphous silica-titania composite oxide powder which is powder untreated with a surface treatment agent and consisting of amorphous silica-titania composite oxide particles,

• wherein:
• a refractive index of the particles as measured by immersion method at a measurement wavelength of 589 nm is not less than 1.46;
• a volume-based cumulative 50% diameter as measured by laser diffractometry is in a range of 0.1 μm to 2.0 μm;
• and
• a content of particles having a particle size of not less than 5.0 μm is not more than 10 ppm as measured by Coulter counter method, and
• wherein, in a case where the silica-titania composite oxide powder is dried in an atmospheric air at 110° C. for 12 hours, and powder thus dried is stored for 24 hours under conditions of a temperature of 25° C. and a relative humidity of 85% so as to absorb moisture, a water absorption rate is not more than 0.8% by mass as calculated from a change in mass in accordance with the following formula:
• water absorption rate=(Y−X)/X×100
• where X is a mass before moisture absorption, and Y is a mass after the moisture absorption.