Anomalies in the infra-red spectra of ammonium carbonate and ammonium bicarbonate prepared by alkali halide pellet technique

Abstract

Certain anomalies were found in the infra-red spectra of (NH₄)₂CO₃ and NH₄HCO₃ prepared by the alkali halide pellet technique. The causes of these anomalies found in infra-red spectra are as follows. (1) When NH₄HCO₃ is mixed with a large amount of NaCl, a double decomposition reaction occures simultaneously, resulting in the formation of NaHCO₃ and NH₄Cl. However, when NH₄HCO₃ is mixed with KBr, KCl, and KI, such a reaction does not occur. (2) When NH₄HCO₃ is mixed with a large amount of KBr, and placed in a high humidity room, double decomposition takes place, but in a low humidity room, self-decomposition occures. (3) When (NH₄)₂CO₃ is mixed witha large amount of KBr, and placed in a variable humidity room, it changes gradually to NH₄Br.