synthesized with hydrazine oxalic acid and tungstic acid in different ratios and a series of tungsten oxides, O/W ratios from 2.90 to 2.30,were obtained by thermal decomposition from the precursors under nitrogen atmosphere at 640～760℃. This kind of tungsten oxides were found to belong to mixed valence compounds which have some special electrical properties. The experimental result indicated that the electrical conductivity of this tungsten oxide has a close relation with its O/W ratio and reach the maximum at WO2.50. Seclecting WO2.50 as an example, its conductivity was measured at different temperatures from -197 ℃to -2.5 ℃and it was found that the mixed valence tungsten oxide as conductor belongs to the class of metal ones. Owing to their relatively high electrical conductivity and stability in air, mixed valence tungsten oxide shows some potential use in polymer products as additives.
