Solid-state anomalies in IR spectra of compounds of pharmaceutical interest

Solid-state anomalies in the IR spectra of lysine monohydrochloride, etoxadrol hydrochloride, thiamine hydrochloride, and L-histidine in a potassium bromide matrix were noted. With the first three compounds, the anomalies were due to metathetical exchange of the halide anion between the compound and the matrix. The anomaly seen with L-histidine was related to the crystal structure.