Powdery silica composite particles, a method of manufacturing the same, silica composite particle dispersion, and the resin composition

An object of the invention is to provide a substance enabling uniformly dispersing an ionic liquid or a phosphonium salt in various solvents, resin materials, and the like. A powdery silica composite particle obtained by a surface treatment step comprising providing a reaction solution by mixing a silica sol containing a core silica particle having an average particle size of 5 to 200 nm, an alkoxysilane, and an ionic liquid and hydrolyzing the alkoxysilane by addition of an acid or an alkali to the reaction solution to surface-treat the core silica particle.