ISSN:
1572-8927
Keywords:
Raman spectroscopy
;
zinc bromide complexing
;
aqueous high temperature electrolyte solutions
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract A Raman spectral study of 14 solutions of varying bromide to zinc ratios was conducted up to 300°C and 9 MPa. The tetra-, tri-, di- as well as the mono-bromozinc complexes were identified. The signal from the ZnBr+ complex increased in intensity as temperature increased, for solutions of low bromide- to-zinc ratios. The ZnBr 4 2− species was favored at higher Br/Zn ratios, and higher temperatures favored the formation of the species ZnBr2 and ZnBr+ at the expense of ZnBr 4 2− and ZnBr 3 − . Although solvated water is probably present in these zinc-bromo complexes, we found no evidence of O−Zn vibrations other than for Zn(H2O) 6 2+ . However, spectra of successive dilutions of solutions with high bromide to zinc ratios show a relative change in species populations thereby suggesting that water activity plays a decisive role in complex formation. For the first time trifluoromethanesulfonic acid (HTFMS) has been used as an internal standard in Raman spectroscopy. This permitted quantitative measurement of stepwise stability constants.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00647420
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