Computational and Experimental 1H-NMR Study of Hydrated Mg-Based Minerals.

Eric G Sorte,Jessica M Rimsza,Todd M Alam

doi:10.3390/molecules25040933

Abstract

Magnesium oxide (MgO) can convert to different magnesium-containing compounds depending on exposure and environmental conditions. Many MgO-based phases contain hydrated species allowing 1H-nuclear magnetic resonance (NMR) spectroscopy to be used in the characterization and quantification of proton-containing phases; however, surprisingly limited examples have been reported. Here, 1H-magic angle spinning (MAS) NMR spectra of select Mg-based minerals are presented and assigned. These experimental results are combined with computational NMR density functional theory (DFT) periodic calculations to calibrate the predicted chemical shielding results. This correlation is then used to predict the NMR shielding for a series of different MgO hydroxide, magnesium chloride hydrate, magnesium perchlorate, and magnesium cement compounds to aid in the future assignment of 1H-NMR spectra for complex Mg phases.

Highlights

Magnesium oxide (MgO) is used in many engineering applications because of its unique material properties
The 1 H-magic angle spinning (MAS)-nuclear magnetic resonance (NMR) spectra of crystalline Mg-based phases was combined with periodic density functional theory (DFT)
NMR calculations to produce a correlation between the computed chemical shielding tensor and the experimental chemical shift to be used for referencing hydroxylated and hydrated Mg materials

Summary

Introduction

Magnesium oxide (MgO) is used in many engineering applications because of its unique material properties. MgO has been used for construction [4,5], optics [6,7], medicine [8,9], fertilizers [10], electronics [11,12], catalysis [13], chemical warfare agent decontamination [14], high temperature super conductors [15], hydrogen storage [16,17], and nuclear waste storage [18,19] For many of these applications, the performance of. Our interest is the identification of protonated impurities in MgO [20]: a material that is currently used as an engineered barrier for carbon remediation at the DOE Waste Isolation Pilot Plant (WIPP) located near Carlsbad, New Mexico

Methods

Discussion

Conclusion