The laser Raman and infrared spectra of Li, Na, K, Rb, Cs bicarbonates and carbonates in H2O and D2O have been determined at 25 °C. The relative integrated intensities of the Raman bands have been measured for each salt from 0.01 M up to saturation. Changes observed in the carbonate spectrum with concentration have been interpreted in terms of solvation and ion-pairing of the carbonate ion. Based on the vibrational spectrum, there was no evidence for ionic interactions in the bicarbonate solutions. The hydrogen–deuterium exchange on the bicarbonate ion in H2O–D2O mixtures has been followed using Raman spectroscopy and the concentration quotients for the pertinent reactions have been calculated.