Croatica Chemica Acta, Vol. 82 No. 2, 2009.
Original scientific paper
Association of Nitrate Ion with Metal Cations in Aqueous Solution: a UV-Vis Spectrometric and Factor-Analytical Study
Vlatka Gvozdić
; Department of Chemistry, Josip Juraj Strossmayer University of Osijek, Franje Kuhača 20, 31000 Osijek, Croatia
Vladislav Tomišić
orcid.org/0000-0002-1191-2123
; Laboratory of Physical Chemistry, Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia
Vjekoslav Butorac
; Laboratory of Physical Chemistry, Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia
Vladimir Simeon
; Laboratory of Physical Chemistry, Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia
Abstract
Ion association in aqueous solutions of varied concentrations of LiNO3, NaNO3, Ca(NO3)2, Sr(NO3)2, Ba(NO3)2, Mn(NO3)2, Co(NO3)2, Ni(NO3)2, Cu(NO3)2, Zn(NO3)2, and Cd(NO3)2 was studied by means of UV spectrometry. In all cases, except for Zn(NO3)2(aq) the principal-components (PCA) and evolving-factor (EFA) analyses of the spectra indicated formation of associated ion pairs [MNO3]z-1 (Mz denotes the cation) at higher salt concentrations. The (dis)similarities of the [MNO3]z-1 (Mz spectral profiles (computed by EFA) were examined by means of cluster analysis. The influence of transition-metal ions on the nitrate UV spectrum was found to be remarkably different compared to that of non-transition cations. That could be a consequence of different types of cation-anion interactions. The ion pairs containing non-transition metal ions could be regarded as classical electrostatic ones, whereas a weak coordination interaction was presumably present in the ion pairs formed by the nitrate and the cations of transition metals.
Keywords
ion association; nitrate; UV spectrometry; principal components analysis; evolving factor analysis; cluster analysis
Hrčak ID:
39678
URI
Publication date:
15.7.2009.
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