Methodological progress in trace amounts of structural water in nominally anhydrous minerals

• Published in: Science China. Earth Sciences Vol. 59; no. 5; pp. 901 - 909
• Main Authors: Sheng, YingMing, Gong, Bing, Li, WanCai, Xia, Mei
• Format: Journal Article Book Review
• Language: English
• Published: Beijing Science China Press 01.05.2016; Springer Nature B.V
• Subjects: Earth and Environmental Science; Earth Sciences; Hydrology; Minerals; Molecular biology; Review; Water; 傅立叶变换红外光谱法; 化学公式; 含水矿物; 微量元素; 无水; 物理化学性质; 结构位置; 结构水; Molecular water; Fourier transform infrared spectrometry; Structural hydroxyl; Nominally anhydrous minerals; Water content
• ISSN: 1674-7313; 1869-1897
• DOI: 10.1007/s11430-016-5281-0

In the deep Earth, hydrogen mainly occurs as structural hydroxyl and molecular water in minerals and melts, constituting mobile and immobile aqueous components. Hydrous minerals contain hydrogen which occupies a specific structural position and constitutes an indispensable component of chemical formulae. On the other hand, nominally anhydrous minerals do not contain hydrogen in their chemical formulae, but can host trace amounts of water in structural position and lattice defect. The molecular water may occur in the lattice defect as fluid/melt inclusions in minerals. Even though the water content of nominally anhydrous minerals is very limited generally in the order of ppm（parts per million）, they may play a significant role in influencing the physicochemical properties of mineral and rock systems. With the continuous improvement of modern instrumentations, the analytical methodology exhibits trends for higher spatial resolution, lower detection limit and integral multiple methods on the water amount and its isotopic ratio. Among these methods, Fourier transform infrared spectrometry remains the most widely used, while secondary ion mass spectrometry, continuous flow mass spectrometry, elastic recoil detection analysis and Raman spectrometry are promising. This paper provides a brief review on the methodological progress and their applications to the analysis of structural water in nominally anhydrous minerals.