Preparation of SnO₂ whiskers via the decomposition of tin oxalate

A new method for preparing SnO₂ whiskers by the decomposition of SnC₂O₄ is suggested. A Whisker-like morphology of a SnC₂O₄ precipitate was attained via the gradual addition of an oxalic acid solution to a hot SnCl₂ aqueous solution (T > 50°C). In comparison, when the solution temperature was either lower than 50°C or when ethanol was used as the solvent, the SnC₂O ₄ precipitate showed an angular and relatively isotropic morphology. The morphology of the SnC₂O₄ precipitate remained even after its thermal decomposition into SnO₂ at 400°C indicating that SnC₂O₄ precipitation is a key step in preparing the whiskers. The formation mechanism of SnO₂ whiskers was explained by the supersaturation during the precipitation of SnC₂O₄.