Proton Distributions and Hydrogen Bonding in Crystalline and Glassy Hydrous Silicates and Related Inorganic Materials: Insights from High‐Resolution Solid‐State Nuclear Magnetic Resonance Spectroscopy

Abstract

Solid‐state 1H nuclear magnetic resonance (NMR) spectroscopy has developed into a versatile, high‐resolution method for elucidating the detailed structures of both crystalline and amorphous materials. Here, we summarize our recent endeavors in applying this method to crystalline and glassy silicates and related inorganic materials. We first present updated correlations between 1H chemical shift and O⋯O and H⋯O distances of O–H⋯O hydrogen bonds, derived from a comprehensive 1H chemical shift database containing both original high‐quality fast magic angle spinning (MAS) and two‐dimensional combined rotation and multiple pulse spectroscopy (CRAMPS)‐MAS NMR data and literature MAS NMR data for a large number of inorganic compounds, including phosphates, silicates, (oxy)hydroxides, borates, sulfates, and carbonates. These correlations may be used to estimate hydrogen‐bonding distances for inorganic oxide materials of unknown structures. We then present case studies for the application of high‐resolution two‐dimensional 1H CRAMPS‐MAS NMR to unravel the order/disorder of proton distributions in crystalline high‐pressure hydrous silicates. Finally, we summarize some of our results on the water speciation in hydrous (alumino)silicate glasses of a range of compositions obtained through comprehensive 1H MAS NMR, and 29Si–1H and 27Al–1H double‐resonance NMR experiments, and analyze them in the framework of a quasi‐chemical model.

Water in the Earth's mantle: a solid-state NMR study of hydrous wadsleyite

“…The spectrum exhibits an intense resonance at $4 ppm, together with a broad 'shoulder' at approximately 2 ppm. These chemical shis are consistent with other measurements of hydroxyl protons in Mg-OH environments, 69,70 and are therefore consistent with the main mechanism of hydrogen atom incorporation being protonation of the O1 site. However, in addition to this main region of intensity, weaker resonances are also observed between approximately 6 and 10 ppm.…”

In situ study of the fractionation of hydrogen isotopes between aluminosilicate melts and coexisting aqueous fluids at high pressure and high temperature – Implications for the δD in magmatic processes

“…see Stolper, 1982;Nowak and Behrens, 1995;Sowerby and Keppler, 1999;Behrens and Yamashita, 2008;Moretti et al, 2014) and chemical composition (e.g. see Robert et al, 2001;Behrens and Yamashita, 2008;Xue and Kanzaki, 2009;Le Losq et al, 2015). In addition, H environments have a broad distribution of oxygen-oxygen distances, as testified by the large signals assigned to O-H stretching vibrations, observed in Raman or IR spectra of glasses (Le Losq et al, 2012) or in 1 H NMR spectra (Eckert et al, 1988;Robert et al, 2001;Cody et al, 2005;Le Losq et al, 2015).…”

“…Hydrogen (and hence, D) can form Si-OH bonds or metal-OH bonds (e.g. Cody et al, 2005;Xue and Kanzaki, 2009) or present as H 2 O. Its speciation and environments are strongly dependent on temperature (e.g.…”

Multinuclear NMR study of Cs-bearing geyserites of the Targejia hot spring cesium deposit in Tibet

“…The dominant peak at ~4 ppm is assigned to water within geyserite (Paris et al 2007). 1 H NMR peaks above 7 ppm correspond to the protons strongly bonded to the non-bridging oxygen atoms (Hansen et al 2008(Hansen et al , 2009Xue and Kanzaki 2009), therefore, the broad shoulder between 6.5 and 8 ppm may result from strong hydrogen-bonded hydroxyls, internal Q 2 and Q 3 silanols, residual physisorbed water molecules, or Cs environments such as Si-OH-Cs. These assignments are consistent with those in opals by Paris et al (2007).…”