The natural hydrous sodium−magnesium sulfate blödite (astrakhanite) Na2Mg(SO4)2 · 4H2O from sediments of saline Lake Bai Shagyr (Russia) is studied. The stages of its decomposition on heating are distinguished using thermal analysis, X-ray diffraction, IR and Raman spectroscopy. The enthalpy of formation of blödite from elements (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\Delta }_{f}}H_{{el}}^{0}$$\end{document} (298.15 K) = –3845 ± 13 kJ/mol) is determined on a Tian-Calvet microcalorimeter using high-temperature melt solution calorimetry. The values of standard entropy and Gibbs energy of mineral formation are estimated.

中文翻译：

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Blödite（Astrakhanite）的热和热化学研究

研究了来自盐湖 Bai Shagyr（俄罗斯）沉积物中的天然含水硫酸镁钠盐（astrakhanite）Na2Mg(SO4)2 · 4H2O。使用热分析、X 射线衍射、IR 和拉曼光谱可以区分其加热分解的阶段。从元素形成 blödite 的焓 (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{ upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\Delta }_{f}}H_{{el}}^{0}$$\end{document} (298.15 K) = –3845 ± 13 kJ/mol) 是在 Tian-Calvet 微量热仪上使用高温熔体溶液量热法测定的。估计矿物形成的标准熵和吉布斯能的值。