The so-called phenylthiohydantoic acid: its structure and application to the gravimetric determination of cobalt
Abstract
The compound previously known as phenylthiohydantoic acid is shown to be carbaminothioglycollic acid anilide. The precipitate produced when this reagent is added to cobalt solutions is tris(thioglycollic acid anilido) cobalt(III), formed by hydrolysis of the carbamino compound. This precipitate is not formula-pure, however, and cannot be weighed directly. It must be ignited to tricobalt tetra-oxide, Co3O4, for the determination of cobalt.