Phase-pure brookite of high crystallinity, which was classically obtained via hydrothermal treatment, has been synthesized under ambient pressure at 70degreesC via reacting a mixed solution of urea and titanium (III) chloride (instead of the widely used titanium (IV) compounds). The resultant particles are monodispersed spheres (similar to154 nm) composed of brookite nanocrystals (similar to25 nm), which are stable in terms of phase purity and morphology up to similar to500degreesC, above which a direct transition to rutile occurred. The as-made powder has a high specific surface area of similar to41.2 m(2)/g, which rapidly decreased to similar to9.7 m(2)/g after transforming to rutile at 700degreesC. The brookite powder shows good catalytic property for the decomposition of acetaldehyde under UV radiation.