Collect. Czech. Chem. Commun. 1981, 46, 1764-1774

Extraction study of hafnium complexes with aliphatic hydroxy acids

Jiří Hála and Petr Londýn

Department of Inorganic Chemistry, Purkyně University, 611 37 Brno


Hafnium complexes with glycolic, lactic, malic, tartaric and citric acids were studied in perchlorate medium (1.0-3.0 mol l-1 HClO4) by using the competitive extraction method. In the hydroxy acid concentration region 0.01-1.0 or 2.0 mol l-1, complexes with the hafnium-to-ligand ratios 1 : 1 and 1 : 2 (in the case of lactic and malic acids also 1 : 3) were identified and their stability constants determined. One proton is split off during the formation in acidic medium, a five-membered chelate ring being formed with the Hf(IV) cation bonded to the non-dissociated hydroxy group of the ligand.