Abstract
The infrared spectra of some thiohydroxamic acids (I) and their deuterated compounds were investigated and compared with those of some O-methylthiohydroxamic acids (II). It was concluded that I exist in thione-form in the solid state but the both of thiol and thione tautomers exist in the liquid or in the solution, in which state polar solvents favor the former tautomer, whereas II occur in thiol-form in all the states. These facts were more positively confirmed by the NMR spectra and by the determinations of the pKa values. The "N-C=S bands" of the thione-form of I were assigned to the regions 1550±20, 1340±30 and 1085±5cm-1.
