2-(4-Iodophenyl)-3- (4-nitro phenyl)-5-phenyl-2H-tetrazolium chloride 5G

2-(4-Iodophenyl)-3- (4-nitro phenyl)-5-phenyl-2H-tetrazolium chloride is a commonly used tetrazolium salt (usually prepared with chloride ions), similar to tetrazolium chloride that on reduction produces a red formazan dye that can be used for quantitative redox assays.