A Study on Complex Formation of Beryllium with Salicylic and Sulphosalicylic Acids

Beryllium perchlorate (Be2+) forms a colorless complex with salicylic acid as well as with sulphosalicylic acid. The nature of these complexes has been studied by ultraviolet spectrophotometry. The absorption spectra at different pH's suggest that the complex formation increases with an increase in pH. Composition of these complexes has been studied at pH 4.5 by Job's method of continued variation. The molecular ratio of Be2+ to the ligand in both the complexes is 1 : 1. Stability constants have been determined at ionic strengths 0.02, 0.05, 0.1, and 0.2 M for the Be2+ -salicylic . acid complex as well as for the Be2+-sulphosalicylic acid complex. Thermodynamic stability constants have been found by extrapolation and are 1.66 x 104 and 2.24 x 104 for salicylic acid and sulphosalicylic acid complexes respectively; the values of —\(\bigtriangleup\)F's are 5830 and 6010 cals. respectively