Raman Spectra of the Different Phases in the CaSO4鈥揌2O System
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- 作者：Nagore Prieto-Taboada ; Olivia G贸mez-Laserna ; Irantzu Mart铆nez-Arkarazo ; Mar铆a 脕ngeles Olazabal ; Juan Manuel Madariaga
- 刊名：Analytical Chemistry
- 出版年：2014
- 出版时间：October 21, 2014
- 年：2014
- 卷：86
- 期：20
- 页码：10131-10137
- 全文大小：296K
- ISSN：1520-6882
文摘
Although it is known that the CaSO4/H2O system is formed by at least five different phases, this fact is not correctly documented in Raman spectroscopy studies. The main problem detected in the literature was the incorrect definition of the anhydrite, which produced the assignation of different spectra for a single compound. In this sense, two different spectra were clearly identified from the bibliography, which showed different main Raman bands at 1017 or 1025 cm鈥?, although anhydrite could be present even as three different polymorphous species with different structures. A better understanding of the whole system obtained from a review of the literature allowed new conclusions to be established. Thanks to that revision and the development of different thermodynamical experiments by Raman spectroscopy, the Raman spectra of each phase were successfully identified for the first time. In this way, the main Raman bands of gypsum, bassanite, anhydrite III, anhydrite II and anhydrite I were identified at 1008, 1015, 1025, 1017 and 1017 cm鈥?, respectively. To conclude this work, the contradictions found in literature were critically summarized.