INFRARED SPECTRA OF GASEOUS $H_{2}SO_{4}$
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Date
1965
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
The spectra in the region $4000-400 cm^{-1}$ of the vapors above liquid $H_{2}SO_{4}, D_{2}SO_{4}, HDSO_{4}$ and solutions of $H_{2}O$ or $SO_{3}$ in these acids were studied. Also measured were the spectra of analogous gaseous compounds and of liquid $HDSO_{4}$. Up to $100^{\circ} C$, only the $SO_{3}(g)$ spectrum was observed above the $H_{2}SO_{4}-SO_{3}$ mixtures. Above $H_{2}SO_{4}$ or $H_{2}SO_{4}-H_{2}O$ mixtures, a new spectrum assigned tentatively to $H_{2}SO_{4}(g)$ was measured between $180^{\circ}$ and $250^{\circ}C$. No $SO_{3}$ was observed. The presence of water in the solution did not alter the spectrum. Bands assigned to the O-H(D) stretch were observed at 3611 and $2663 cm^{-1}$ above $H_{2}SO_{4}(D_{2}SO_{4})$, implying little hydrogen bonding in the gas. The $HDSO_{4}(g)$ spectrum in this region is exactly a superposition of these two bands. Similarly, liquid $HDSO_{4}$ showed no new bands. Under the assumption that $H_{2}SO_{4}$ gives rise to this spectrum, it must be assumed that there is little interaction between the two $O-H$ stretching motions. The structure $(HO)_{2}SO_{2}(g)$ is implied. The remainder of the spectrum is similar to that of the liquid. Bands assigned to the $S=O$ stretching frequencies were higher than in the liquid, whereas the $S-[OH(D)]$ stretching and the $S-O-[OH(D)]$ and $O=S=O$ bending frequencies were lower.
Description
Author Institution: Department of Chemistry and Materials Research Center, Northwestern University Evanston, Illinois, 60201
Supported by the U. S. Army Research Office-Durham.
Supported by the U. S. Army Research Office-Durham.