Deposition of Copper(II) Hydroxosulfates by Urea

The composition of the products deposited from urea-containing solutions of copper(II) sulfate is studied as a function of concentration of the reactants, their molar ratio, and temperature and time of thermal processing. Depending on the conditions, the deposited solids are pure brochantite Cu4(OH)6SO4 · 0.25H2O (I), antlerite Cu3(OH)4SO4 (II), and poznyakite Cu4(OH)6SO4 · H2O (III) or Cu7(OH)10(SO4)2 · H2O (IV) or mixtures of compounds I and II, of II and IV, or of III and IV. Compounds I-IV are characterized by IR spectroscopy, chemical analysis, crystal-optical analysis, and X-ray powder diffraction.