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Diffraction Studies on Concentrated Aqueous Hydrochloric Acid Solutions
Author(s) -
Kameda Yasuo,
Usuki Takeshi,
Uemura Osamu
Publication year - 1999
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.199900035
Subject(s) - chemistry , intermolecular force , hydrochloric acid , neutron diffraction , aqueous solution , hydrogen bond , crystallography , diffraction , x ray crystallography , analytical chemistry (journal) , deuterium , molecule , inorganic chemistry , crystal structure , organic chemistry , atomic physics , physics , optics
X‐ray diffraction and neutron diffraction experiments with H/D isotopically substituted aqueous 21 mol% hydrochloric acid solutions were carried out in order to obtain detailed features concerning the intermolecular hydrogen‐bonded structure in highly concentrated aqueous acidic solutions. Structure parameters, namely, intermolecular distance, root‐mean‐square amplitude, and coordination number, for the nearest neighbor H 3 O + ···H 2 O interaction were determined from the least‐squares‐fitting analysis of the observed X‐ray interference term. These were, respectively, r (H 3 O + ···H 2 O) = 2.45(1) Å; l (H 3 O + ···H 2 O) = 0.11(1) Å; and n (H 3 O + ···H 2 O) = 1.8(1). The intermolecular nearest neighbor distances, r (H···H) = 2.02(5) Å and r (O···H) = 1.69(2) Å, were determined from the least‐squares fit to partial structure factors, a ij ( Q ), derived from the observed neutron intermolecular interference terms for sample solutions with different H/D isotopic ratios. The present values of intermolecular distances are significantly shorter than those for pure liquid water, implying that extremely strong hydrogen bonds exist in concentrated aqueous acidic solutions.