ULTRAVIOLET AND ULTRASONIC ABSORPTION SPECTRAL STUDIES OF ASSOCIATION OF CUSO4 AND CU(EN)2S2O3 IN WATER AT 25 DEGREES

Spectrophotometric absorbance measurements of aqueous solutions of CuSO4 and Cu(en)2S2O3 at constant ionic strength in the ultraviolet region are reported. Analysis of the data together with existing literature values leads to the conclusion that the association constant of the two electrolytes is the same within experimental errors, K̄ = 220-230 M-1. Ultrasonic absorption measurements on the same systems show the same relaxation frequency, fr = 170 ± 10 Mcps. After analysis of the data, the results are interpreted by a mechanism in which the same process is observed for both electrolytes, namely, the elimination of an axial water molecule from the distorted octahedron of Cu2+(aq) or Cu2+(en)2(aq), this process being coupled to a faster diffusion approach between solvated ions.