التفاصيل البيبلوغرافية
| العنوان: |
EPR Spectroscopic and Calorimetric Study of Minerals of the Amblygonite–Montebrasite Series from Rare-Metal Pegmatite of the Voron'i Tundras (Kola Peninsula) and Sangilen Highlands (Tuva). |
| المؤلفون: |
Vyatkin, S. V.1 (AUTHOR), Gritsenko, Yu. D.1,2 (AUTHOR) ygritsenko@rambler.ru, Ogorodova, L. P.1 (AUTHOR) logor48@mail.ru, Vigasina, M. F.1 (AUTHOR), Ksenofontov, D. A.1 (AUTHOR), Melchakova, L. V.1 (AUTHOR) |
| المصدر: |
Geochemistry International. Jul2024, Vol. 62 Issue 7, p748-759. 12p. |
| مصطلحات موضوعية: |
*HEAT of formation, *ELECTRON paramagnetic resonance spectroscopy, *GIBBS' free energy, *CRYSTAL lattices, *PEGMATITES |
| مستخلص: |
The paper reports the first comprehensive physicochemical study of minerals of the amblygonite LiAlPO4F–montebrasite LiAlPO4(OH) series. An EPR spectroscopic and calorimetric study of montebrasite LiAlPO4(OH)0.9F0.1 from the Shuk-Byul rare-metal granite pegmatites (Sangilen Highlands, Tuva) and amblygonite LiAlPO4F0.5(OH)0.5 from pegmatites of the Voron'i Tundras (Kola Peninsula) was carried out. Using the EPR method, the radiation-sensitive paramagnetic O– centers were discovered. They were formed without participation of impurity elements in the regular sites of crystal lattice. The possibility use of minerals of the amblygonite–montebrasite series for EPR geochronometry has been demonstrated for the first time. Using the method of high-temperature melt dissolution calorimetry on a Tian-Calvét microcalorimeter, the enthalpies of formation from elements (298.15 K) = –2326.3 ± 2.2 kJ/mol for montebrasite with the composition LiAl(PO4)(OH)0.9F0.1 and for amblygonite with the composition LiAl(PO4)F0.5(OH)0.5 (‒2347.9 ± 3.1 kJ/mol) are obtained; and the values of this parameter are calculated for the end members with an ideal composition of the series: for montebrasite (–2315.5 ± 2.2 kJ/mol) and for amblygonite (–2401.6 ± 3.1 kJ/mol). The values of the standard entropy S0 (298.15 K) and the Gibbs energy of formation (298.15 K) for intermediate and end members of the amblygonite–montebrasite series are estimated. [ABSTRACT FROM AUTHOR] |
| قاعدة البيانات: |
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