DOI: 10.1139/v81-372. Resolution of Raman spectra of aqueous sulfuric acid mixtures using principal factor analysis

Resolution of Raman spectra of aqueous sulfuric acid mixtures using principal factor analysis

10.1139/v81-372

Crossref journal-article

Canadian Science Publishing

Canadian Journal of Chemistry (155)

Abstract

Principal factor analysis has been applied to Raman spectra of 26 sulfuric acid/water mixtures covering the 0–100% H2SO4 concentration range. The analysis greatly facilitates the identification of peaks due to different species. The results show that SO42− ions and "free" HSO4− ions do not co-exist with undissociated H2SO4 molecules in solution and that two water molecules rather than one are required for the first ionization of H2SO4. A species with the composition H2SO4•2H2O, assigned a hydrated ion pair structure, reaches maximum concentration at the same medium composition at which SO42−, free HSO4−, and H2SO4 are at concentration minima, about 75% w/w. The only species apparent in the more concentrated solutions are the ion pair and undissociated H2SO4, which could be taken to mean that H2SO4 is a weaker acid than H3O+, but a stronger one than H3O+•H2O (or H5O2+, if this entity has a real existence). Separate peaks due to the postulated H3O+•H2SO4 (or H5SO5+) were not observed.

Bibliography

Cox, R. A., Haldna, Ã. L., Idler, K. L., & Yates, K. (1981). Resolution of Raman spectra of aqueous sulfuric acid mixtures using principal factor analysis. Canadian Journal of Chemistry, 59(17), 2591â2598.

Authors 4

Robin A. Cox (first)
Ülo L. Haldna (additional)
K. Loralee Idler (additional)
Keith Yates (additional)

References 0 Referenced 40

None

Dates

Type	When
Created	19 years, 3 months ago (May 8, 2006, 11:21 a.m.)
Deposited	1 month, 3 weeks ago (July 2, 2025, 2:13 p.m.)
Indexed	1 month ago (July 23, 2025, 8:38 a.m.)
Issued	43 years, 11 months ago (Sept. 1, 1981)
Published	43 years, 11 months ago (Sept. 1, 1981)
Published Print	43 years, 11 months ago (Sept. 1, 1981)

Funders 0

None

BibTeX

@article{Cox_1981, title={Resolution of Raman spectra of aqueous sulfuric acid mixtures using principal factor analysis}, volume={59}, ISSN={1480-3291}, url={http://dx.doi.org/10.1139/v81-372}, DOI={10.1139/v81-372}, number={17}, journal={Canadian Journal of Chemistry}, publisher={Canadian Science Publishing}, author={Cox, Robin A. and Haldna, Ülo L. and Idler, K. Loralee and Yates, Keith}, year={1981}, month=sep, pages={2591–2598} }

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  "abstract": "<jats:p> Principal factor analysis has been applied to Raman spectra of 26 sulfuric acid/water mixtures covering the 0\u2013100% H<jats:sub>2</jats:sub>SO<jats:sub>4</jats:sub> concentration range. The analysis greatly facilitates the identification of peaks due to different species. The results show that SO<jats:sub>4</jats:sub><jats:sup>2\u2212</jats:sup> ions and \"free\" HSO<jats:sub>4</jats:sub><jats:sup>\u2212</jats:sup> ions do not co-exist with undissociated H<jats:sub>2</jats:sub>SO<jats:sub>4</jats:sub> molecules in solution and that two water molecules rather than one are required for the first ionization of H<jats:sub>2</jats:sub>SO<jats:sub>4</jats:sub>. A species with the composition H<jats:sub>2</jats:sub>SO<jats:sub>4</jats:sub>\u20222H<jats:sub>2</jats:sub>O, assigned a hydrated ion pair structure, reaches maximum concentration at the same medium composition at which SO<jats:sub>4</jats:sub><jats:sup>2\u2212</jats:sup>, free HSO<jats:sub>4</jats:sub><jats:sup>\u2212</jats:sup>, and H<jats:sub>2</jats:sub>SO<jats:sub>4</jats:sub> are at concentration minima, about 75% w/w. The only species apparent in the more concentrated solutions are the ion pair and undissociated H<jats:sub>2</jats:sub>SO<jats:sub>4</jats:sub>, which could be taken to mean that H<jats:sub>2</jats:sub>SO<jats:sub>4</jats:sub> is a weaker acid than H<jats:sub>3</jats:sub>O<jats:sup>+</jats:sup>, but a stronger one than H<jats:sub>3</jats:sub>O<jats:sup>+</jats:sup>\u2022H<jats:sub>2</jats:sub>O (or H<jats:sub>5</jats:sub>O<jats:sub>2</jats:sub><jats:sup>+</jats:sup>, if this entity has a real existence). Separate peaks due to the postulated H<jats:sub>3</jats:sub>O<jats:sup>+</jats:sup>\u2022H<jats:sub>2</jats:sub>SO<jats:sub>4</jats:sub> (or H<jats:sub>5</jats:sub>SO<jats:sub>5</jats:sub><jats:sup>+</jats:sup>) were not observed. </jats:p>",
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