Copper(II) hydroxide sulfate was synthesized by a microwave-assisted hydrothermal method from a mixed solution of CuSO4 and urea. Needle-like crystals of ca. 20-30 mu m in length precipitated by irradiating microwave for 1 min were characterized as Cu-3(OH)(4)SO4 corresponding to mineral antlerite. The reaction pathway and kinetics of the thermal decomposition of the synthetic antlerite Cu-3(OH)(4)SO4 were investigated by means of thermoanalytical techniques complemented by powder X-ray diffractometry and microscopic observations. The thermal decomposition of Cu-3(OH)(4)SO4 proceeded via two separated reaction steps of dehydroxylation and desulfation to produce CuO, where crystalline phases of Cu2OSO4 and CuO appeared as the intermediate products. The kinetic characteristics of the respective steps were discussed in comparison with those of the synthetic brochantite Cu-4(OH)(6)SO4 reported previously. (C) 2007 Elsevier B.V All rights reserved.