The combination of a positive charge and reducibility of tetrazolium salts finds use as anticorrosion agents for metals.634,635 The y are components of an oxidant/etchant bath composition for silicon dioxide corrosion — resistant surfaces.636 They are also used as antistatic agents in polyamide
yarns.637,638
Tetrazolium salts have found use as phase transfer catalysts in the oxidation of benzaldehyde640 and toluene193 and the displacement reaction of acid chlorides with sodium azide.639
Formazans and their metal complexes are used as textile dyes by direct application. The in situ reduction of tetrazolium salts has not been used to introduce the dyes to their substrates. Treatment with triaryl mono and bis tetrazolium salts followed by a reducing agent such as ascorbic acid or thioglycolic acid has been claimed as a method of introducing formazans as permanent hair dyes.641 There are some references to their use as therapeutic agents.642-644