Amidines as extractants: spectrophotometric determination of rhenium in ores as its ternary thiocyanato complex

A sensitive method for the spectrophotometric determination of ReIV is described. The method is based on the reduction of ReVII to ReIV by tin(II) chloride in H2SO4 and the extraction of the thiocyanato complex of the metal with amidine into chloroform over an acidity range of 3.5–6.5 M H2SO4. The complexes formed with 11 different amidines have molar absorptivities in the range 1.46 × 104–2.35 × 104 l mol–1 cm–1 with absorption maxima at ca. …