Hydroxyl-type Sc2O3 precursors have been synthesized via precipitation at 80degreesC with hexamethylenetetramine as the precipitant. The effects of starting salts (scandium nitrate and sulfate) on powder properties are investigated. Characterizations of the powders are achieved by elemental analysis, X-ray diffractometry (XRD), differential thermal analysis/thermogravimetry (DTA/TG), high-resolution scanning electron microscopy (HRSEM), and Brunauer-Emmett-Teller (BET) analysis. Hard-aggregated precursors (gamma-ScOOH-0.6H(2)O) are formed with scandium nitrate, which convert to Sc2O3 at temperatures greater than or equal to400 degreesC, yielding nanocrystalline oxides of low surface area. The use of sulfate leads to a loosely agglomerated basic sulfate powder having an approximate composition of Sc(OH)(2.6)(SO4)(0.2).H2O. The powder transforms to Sc2O3 via dehydroxylization and desulfurization at temperatures up to 1000degreesC. Well-dispersed Sc2O3 nanopowders (similar to64.3 nm) of high purity have been obtained by calcining the basic sulfate at 1000degreesC for 4 h. The effects of SO42- on powder properties are discussed.