AN INVESTIGATION OF STRUCTURE OF DISULFITE ION IN AQUEOUS SOLUTION USING RAMAN AND INFRARED SPECTROSCOPIES

The species formed upon preparing saturated solutions of sodium and potassium disulfites (Na2S2O5 and K2S2O5, respectively) have been studied using Raman and infrared (4000-200 cm-1) spectroscopies. These studies are supplemented by an examination of the corresponding solid salts by both techniques. Fifteen lines which are attributable to the disulfite ion appear in the Raman and infrared spectra, and nine of the Raman lines are found to be polarized. These measurements indicate an assignment of this ion to the Cs point group, consistent with its formulation as an asymmetrical species containing a S-S bond in contradiction to earlier vibrational investigations by Simon and coworkers. There is some evidence for the existence of the hydrogen disulfite (HS2O5-) ion. Also, Raman spectra of the sulfite ion (sodium salt) indicate that the degeneracies of the E modes at ca. 930 and ca. 470 cm-1 are removed in concentrated aqueous solution. © 1969, American Chemical Society. All rights reserved.