Electrochemical behaviour of tin in alkali solutions containing halides

Cyclic voltammetric studies were carried out in NaOH solutions containing different amount of halides. This revealed that tin dissolved to passivate the surface to form Sn(OH)2 which was oxidized to SnO2 at higher potentials. Deposition of tin from [HSnO2−] was found to involve Sn(OH)ads whose formation was slow. In presence of Cl−, Br− and I− ions, the passive film formation potential became active. At higher anodic potentials, tin formed soluble halide complexes of the type [Sn(OH)4X2]2−.