Extraction of complexes of metal ions with pyridine oxyazo compounds

Modern state and prospects of the development of investigas tions in the field of extraction of complexes of metal ions (V, In, Cd, Nb, REE, RU, Ta, U, Zr and others) with pyridine oxyazo compoUnds are analyzed. Application of pyridine oxyazo compounds as extraction-photometric reagents is described. Basic methods of oxyazo compounds preparation are considered along with reagent properties and physical-chemical characteristics. Flow diagrams of ion extraction are presented for the above metals. Mechanisms of complexing reactions for metal ions with pyridine oxyazo compounds and stability of forming complexes are considered in detail. Concrete methods of extraction-photometric separation and element determination permitting to find simultaneously several metal ions with similar properties in the case of their joint presence are described