Preparation of copper compounds of different compositions and particle morphologies

Copper compounds of different chemical compositions and particle shapes were prepared by homogeneous precipitation from copper salt solutions in the presence of urea. It was demonstrated that the nature of the anions played an essential role in the properties of the generated solid phase. Thus, Cu(II)-nitrate solutions yielded spherical amorphous particles which had the composition of malachite [Cu₂(OH)₂CO₃], the Cu(II)-chloride solutions gave bipyramidal particles of atacamite [CuCl₂ · 3Cu(OH)₂], and in Cu(II)-sulfate solutions needle-shaped brochantite [3Cu(OH)₂ · CuSO₄] or platelets of posnjakite [3Cu(OH)₂ · CuSO₄ · H₂O] were formed. The addition of NaOH to prepared dispersions resulted in a rapid phase transformation of all above solids into needle-like Cu(OH)₂. Calcination of various copper basic compounds at 700–800 °C temperature produced CuO, while the particle morphology was retained.