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The nature of the ‘free’ OH groups in water
Author(s) -
Giguère Paul A.,
PigeonGosselin Marie
Publication year - 1986
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1250170409
Subject(s) - raman spectroscopy , hydrogen bond , chemistry , hydrogen peroxide , molecule , aqueous solution , liquid water , proton , acceptor , ion , hydrogen , crystallography , inorganic chemistry , organic chemistry , physics , quantum mechanics , optics , thermodynamics , condensed matter physics
The shoulder at the high‐frequency edge of the O‐H stretching bands in the Raman spectra of liquid water is suppressed by addition of about 12 mol% of hydrogen peroxide. This is further evidence for ‘free’ OH groups, i.e. non‐hydrogen‐bonded (NHB), in water, in contrast with liquid hydrogen peroxide. According to a new model, water contains two kinds of hydrogen bonds: the linear bonds (LHB), as in ice, and the bifurcated bonds (BHB) between three molecules. This upsets the ideal 1:1 ratio of proton donor to proton acceptor sites, creating a slight excess of the former, hence the ‘free’ OH groups. Their concentration at room temperature is only of the order of 1–2% from comparison with the spectra of the OH − ion in aqueous solutions. There are no ‘free’ H 2 O molecules in liquid water.