Complexation reactions between methylthymol blue and Fe , A l ,Ga ,
1n a nd TI ions have been studied in buffer aqueous solutions of pH 5.0 at
2S°C by a spectrophotometric technique. The conditional stepwise stability
constants of the resulting 1:l and 1:2 (metal-to-ligand) complexes were determined
from the absorbance-mole ratio data at three different wavelengths of the
visible spectra. The overall stabilities of the resulting complexes vary in the
order A l > Fe > G a = 1n > T1 .