EXTRACTION-SPECTROPHOTOMETRIC DETERMINATION OF NIOBIUM AND TANTALUM

The 2,4 dihydroxitiophenol forms with Nb and Ta colored complexes which are insoluble in non-polar organic solvents. When aniline includes to the system extraction of these compounds to the organic phase mixed-ligand complexes are observed. The maximum degree of extraction of mixed-ligand complexeses were observed at pH 2.9–8.2. Extracts of Nb(V)–DHTP–An, Ta(V)–DHTP–An are absorbing at 420 (ε = 3.75∙104) and 418 (ε = 3.3∙104) nm, respectively