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Characterizing Lewis Pairs Using Titration Coupled with In Situ Infrared Spectroscopy
Published on: February 20, 2020
[Raman spectroscopic study of the complex and quantitative analysis in the system CuCl2-H2O and FeCl3-H2O]
1The Institute of Mineral Resources, Chinese Academy of Geological Sciences, MLR Key Laboratory of Mefallogenesis and Resource Assessment, Beijing 100037, China. yangd_2004@yahoo.com.cn
Abstract:
In the present paper, the Raman peaks of complex in the CuCl2-H2O system and FeCl3-H2O system were studied in detail. In the CuCl2-H2O system, the superimposed characteristic peaks of various complex formed by Cu2+ and Cl- (such as [CuCl4]2- and [CuCl6]4-) may be formed the peak of 286 cm(-1), and the superimposed characteristic peaks of various complex formed by Cu2+ hydrate([Cu(H2O)4]2+ and [Cu(H2O)6]2+ based) may be formed the peak of 412 cm(-1); Through the analysis of peak parameters, we has founded two quantitative relationships: (1) The peak intensity ratio (I1 I3I 400 or I2/I3 400) of 286 cm(-1) (or 412 cm(-1)) and OH stretching Raman spectrum of water (at 3 400 cm(-1)) and concentration; (2) The integral area of 286 cm(-1) (or 412 cm(-1)) and concentration. In the FeCl3-H2O system, 173 and 331 cm(-1) might be attributed to [FeCl4]- that is the most common form of FeCl3 complex in aqueous solution. The superimposed characteristic peaks of various complex formed by Fe3+ and Cl- (such as [FeCl]2+, [FeCl2]+ etc) may be formed the broad peak of 173 cm(-1), and the superimposed characteristic peaks of various complex formed by Fe3+ hydrate([Fe(H2O)4]3+ and [Fe(H2O)6]3+ based) may be formed the broad weak peak behind of 331 cm(-1). Through the analysis of peak parameters, we has founded two quantitative relationships: (1) The integral area of 331 cm(-1) (A2) and concentration; (2) The integral area ratio of 173 and 331 cm(-1) (A1/A2) and concentration.
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