A Raman spectroscopic study of the equilibria in aqueous solutions of Hg(II) chloride

1985 ◽  
Vol 63 (8) ◽  
pp. 2303-2307 ◽  
Author(s):  
Patrice B. Bentham ◽  
Cynthia G. Romak ◽  
Herbert F. Shurvell
Keyword(s):  
Principal Component Analysis ◽  
Factor Analysis ◽  
Aqueous Solutions ◽  
Spectroscopic Study ◽  
Equilibrium Constants ◽  
Principal Component ◽  
Raman Spectroscopic ◽  
Raman Spectroscopic Study ◽  
Band Contour ◽  
Baseline Fitting

The techniques of factor analysis (principal component analysis) and band contour resolution have been applied to Raman spectra obtained from seven aqueous solutions of HgCl2 with various amounts of HCl added to increase the chloride to mercury ratio. The digitized spectra of the Hg—Cl stretching region (200–380 cm−1) were subjected to baseline fitting and removal, and normalization using the v2 band of ClO4− (380–530 cm−1) as an internal intensity standard. Factor analysis indicated the presence of three scattering components in the Hg—Cl stretching band envelope. Band resolution gave the positions of peaks assigned to HgCl2, HgCl3−, and HgCl42− at 320, 290, and 269 cm−1, respectively. Approximate values for equilibrium constants for the equilibria present in the system have been calculated from the resolved band areas.

Factor analysis as a complement to band resolution techniques. VI. Complex formation between pentachlorophenol-OD and acetone

1979 ◽  
Vol 57 (20) ◽  
pp. 2707-2713 ◽  
Author(s):  
J. Korppi-Tommola ◽  
H. F. Shurvell
Keyword(s):  
Principal Component Analysis ◽  
Factor Analysis ◽  
Complex Formation ◽  
Equilibrium Constant ◽  
Isotope Effect ◽  
Infrared Spectra ◽  
Equilibrium Constants ◽  
Principal Component ◽  
Proton Donor ◽  
Good Agreement

Complex formation between pentachlorophenol-OD (PCP-OD) and acetone and acetone-d6 in CCl4 solution has been studied. Digitized infrared spectra in the O—D stretching region ν(OD) of PCP-OD and the C—O stretching region ν(CO) of acetone have been recorded from solutions of various concentrations. The present results are compared with previous work on complex formation between PCP and the same acceptor molecules. In the ν(OD) region, factor analysis (principal component analysis) and a concentration study of the areas of the resolved band components suggest that two (1:1) complexes occur in solution. The equilibrium constant obtained for one of the complexes shows an isotope effect due to deuteration of the proton donor. In the ν(CO) region, only one band due to complexed species was resolved. Equilibrium constants calculated using the results from the ν(OD) and ν(CO) regions are in good agreement with each other.

Raman Spectroscopic Study of the Ion Association of Lithium Sulfate Aqueous Solutions

1995 ◽  
Vol 50 (2-3) ◽  
pp. 292-300 ◽  
Author(s):  
Fernando Rull
Keyword(s):  
Aqueous Solutions ◽  
Spectroscopic Study ◽  
Association Constant ◽  
Profile Analysis ◽  
Dynamic Properties ◽  
Ion Association ◽  
Sulfate Ions ◽  
Raman Spectroscopic ◽  
Raman Spectroscopic Study ◽  
Band Profile

Abstract A Raman spectroscopic study of Li2SO4 aqueous solutions as function of concentration and temperature was performed. The dynamic properties of the sulfate ions were studied by a band profile analysis of their internal modes using Fourier transform methods. This analysis reveals the perturbation of the SO4-2 vibrations due to ionic interactions. From the v1 (SO4-2) band profile the spectroscopic ionic association constant was calculated in the range from 5 to 80 °C. The large difference found between the values thus obtained for the association constant and the values obtained from macroscopic measurements is interpreted, assuming that Raman spectra reflect only the short-range forces acting on the ions. Using the Bjerrum equation to calculate the contribution for the long-range forces, good agreement is found between the spectroscopic and macroscopic results.

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