Raman spectral study of solutions of N2O4 and N2O5 in nitric acid

✍ Scribed by Jackson E. Harrar; Lester P. Rigdon; Steven F. Rice

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 382 KB
• Volume: 28
• Category: Article
• ISSN: 0377-0486
• DOI: 10.1002/(sici)1097-4555(199711)28:11<891::aid-jrs180>3.0.co;2-z

✦ Synopsis

Solutions of and in anhydrous and aqueous nitric acid were examined by Raman spectroscopy to gain N 2 O 4 N 2 O 5 a more detailed knowledge of the species present in these solutions and to assess the applicability of Raman spectroscopy as an analytical measurement technique. Solutions of in show evidence of the presence N 2 O 4 HNO 3 of the associated species, which had been identiÐed previously in a solid compound. The 3NO' AE NO 3 -(N 4 O 6 2'), e †ects of water on the spectra of these solutions were also examined. The nitronium cation, is the dominant NO 2 ', species in solutions of in anhydrous and the spectra of concentrated solutions of exhibit a N 2 O 5 HNO 3 , N 2 O 5 band that has not been reported previously. This weak band, which may be the same as a band found in the spectra of solids containing the nitronium cation, has been attributed to a second vibrational mode of the molecule. This indicates a nonlinear conformation of the ion, and suggests that it is strongly associated with other species NO 2 ' in solution. The Raman data indicate that in is completely ionized at concentrations to at least 3.0 N 2 O 5 HNO 3 mol l-1 (21 wt% ).