Thermolysis of coprecipitated aluminum and Copper(II) hydroxides

Coprecipitated aluminum-copper(II) hydroxides (CPH) were synthesized on the basis of the stoichiometric correspondence of the amount of OH groups intr oduced into the solution to the amount of Al3+ and Cu2+ ions present, with allowance made for their charge. The formation of CPH with the composition CuAl4(OH)(14)(H2O)(3) upon precipitation from a 1 M solution containing 80 mol % Al3+ and 20 mol % CU2+ was demonstrated by potentiometric titration, differential thermal analysis (DTA), IR spectroscopy, powder X-ray diffract ion analysis, and chemical analysis. These CPH decompose to give the mixed oxide CuA(14)O(7). The X-ray diffraction pattern of this product is similar to that of spinel CuAl2O4.