Abstract: The invention relates to a coating solution for forming transparent conductive tin oxide film, a method for producing transparent conductive tin oxide film, and transparent conductive tin oxide film. The coating solution is capable of forming, from an inexpensive starting material such as tin oxide or tin chloride, strong tin oxide film endowed with excellent conductivity and transparency. The coating solution, which is intended to be used for forming, by way of coating, transparent conductive film predominantly containing tin oxide, contains stannic acid as its major component, and a water-soluble polymer having a polar group which is dissolved in the presence of at least one compound selected from the group consisting of ammonia and water-soluble amines.

Abstract: The invention provides a coating solution for forming transparent silica coating film which solution is stable and can readily form comparatively thick silica coating film on a substrate through single application of the coating solution without use of an organic solvent. The invention also provides a method for producing transparent silica coating film. The coating solution comprising an aqueous solution contains at least one silicon compound which is selected from the group consisting of silicon oxide, silicic acid, and a silicic acid hydrate and which has been modified to have silanol groups; a strong organic base; and a water-soluble polymer, wherein the silicon compound is dissolved in the aqueous solution in presence of the strong organic base.