One of the alkoxyl groups of zirconium tetrabutoxide was allowed to react with carboxylic acids of various chain lengths such as acetic acid, hexanoic acid or decanoic acid and converted to a carboxylato complex. The butoxy groups of this compound were hydrolyzed with alcohol containing water to form a zirconium carboxylato complex. This zirconium carboxylato complex was then subjected to pyrolysis at temperatures up to 1100°C to form ZrO2. It was found that the amounts of tetragonal ZrO2 crystals formed increased as the carbon chain length of the carboxylato group of the zirconium carboxylato complex increased. In terms of morphology, no carboxylato complexes consisting of 2 or 6 carbon chain lengths were observed, however, monodispersed spheres of 1-2 micronmeter in diameter were formed when the carbon chain length was 10.