Skip to content

Research at St Andrews

A picture of disorder in hydrous wadsleyite – under the combined microscope of solid-state NMR spectroscopy and ab initio random structure searching

Research output: Contribution to journalArticle

DOI

Open Access permissions

Open

Author(s)

David McKay, Robert F. Moran, Daniel M. Dawson, John M. Griffin, Simone Sturniolo, Chris J. Pickard, Andrew J. Berry, Sharon E. Ashbrook

School/Research organisations

Abstract

The Earth’s transition zone, at depths of 410–660 km, while being composed of nominally anhydrous magnesium silicate minerals, may be subject to significant hydration. Little is known about the mechanism of hydration, despite the vital role this plays in the physical and chemical properties of the mantle, leading to a need for improved structural characterization. Here we present an ab initio random structure searching (AIRSS) investigation of semihydrous (1.65 wt % H2O) and fully hydrous (3.3 wt % H2O) wadsleyite. Following the AIRSS process, k-means clustering was used to select sets of structures with duplicates removed, which were then subjected to further geometry optimization with tighter constraints prior to NMR calculations. Semihydrous models identify a ground-state structure (Mg3 vacancies, O1–H hydroxyls) that aligns with a number of previous experimental observations. However, predicted NMR parameters fail to reproduce low-intensity signals observed in solid-state NMR spectra. In contrast, the fully hydrous models produced by AIRSS, which enable both isolated and clustered defects, are able to explain observed NMR signals via just four low-enthalpy structures: (i) a ground state, with isolated Mg3 vacancies and O1–H hydroxyls; (ii/iii) edge-sharing Mg3 vacancies with O1–H and O3–H species; and (iv) edge-sharing Mg1 and Mg3 vacancies with O1–H, O3–H, and O4–H hydroxyls. Thus, the combination of advanced structure searching approaches and solid-state NMR spectroscopy is able to provide new and detailed insight into the structure of this important mantle mineral.
Close

Details

Original languageEnglish
Pages (from-to)3024–3036
JournalJournal of the American Chemical Society
Volume141
Issue number7
Early online date24 Jan 2019
DOIs
Publication statusPublished - 20 Feb 2019

    Research areas

  • Ab initio random structure searching, Solid-state NMR spectroscopy, Inner Earth minerals, Disordered materials

Discover related content
Find related publications, people, projects and more using interactive charts.

View graph of relations

Related by author

  1. Hydrolytic stability in hemilabile metal–organic frameworks

    McHugh, L. N., McPherson, M. J., McCormick, L. J., Morris, S. A., Wheatley, P. S., Teat, S. J., McKay, D., Dawson, D. M., Sansome, C. E. F., Ashbrook, S. E., Stone, C. A., Smith, M. W. & Morris, R. E., 13 Aug 2018, In : Nature Chemistry. In press

    Research output: Contribution to journalArticle

  2. Polymorphism, weak interactions and phase transitions in chalcogen-phosphorus heterocycles

    Sanz Camacho, P., Stanford, M., McKay, D., Dawson, D. M., Athukorala Arachchige, K. S., Cordes, D. B., Slawin, A. M. Z., Woollins, J. D. & Ashbrook, S. E. M., 28 Jun 2018, In : Chemistry - A European Journal. Early View

    Research output: Contribution to journalArticle

  3. 17O solid-state NMR spectroscopy of A2B2O7 oxides: quantitative isotopic enrichment and spectral acquisition?

    Fernandes, A., Moran, R., Sneddon, S., Dawson, D. M., McKay, D., Bignami, G. P. M., Blanc, F., Whittle, K. & Ashbrook, S. E., 14 Feb 2018, In : RSC Advances. 8, 13, p. 7089-7101

    Research output: Contribution to journalArticle

  4. Cost-effective 17O enrichment and NMR spectroscopy of mixed-metal terephthalate metal-organic frameworks

    Bignami, G. P. M., Davis, Z. H., Dawson, D. M., Morris, S. A., Russell, S. E., McKay, D., Parke, R. E., Iuga, D., Morris, R. E. & Ashbrook, S. E., 28 Jan 2018, In : Chemical Science. 9, 4, p. 850-859

    Research output: Contribution to journalArticle

  5. Investigating unusual homonuclear intermolecular “through-space” J couplings in organochalcogen systems

    Sanz Camacho, P., McKay, D., Dawson, D. M., Kirst, C., Yates, J. R., Green, T. F. G., Cordes, D. B., Slawin, A. M. Z., Woollins, J. D. & Ashbrook, S. E., 7 Nov 2016, In : Inorganic Chemistry. 55, 21, p. 10881-10887 7 p.

    Research output: Contribution to journalArticle

Related by journal

  1. Journal of the American Chemical Society (Journal)

    David Trevor Richens (Editor)
    2005 → …

    Activity: Publication peer-review and editorial work typesEditor of research journal

Related by journal

  1. Compositional persistence in a multicyclic network of synthetic replicators

    Huck, J., Kosikova, T. & Philp, D., 12 Aug 2019, In : Journal of the American Chemical Society. In press

    Research output: Contribution to journalArticle

  2. Kinetics and mechanism of the hydrolysis and rearrangement processes within the Assembly-Disassembly-Organization-Reassembly synthesis of zeolites

    Henkelis, S. E., Mazur, M., Rice, C. M., Wheatley, P. S., Ashbrook, S. E. M. & Morris, R. E., 13 Mar 2019, In : Journal of the American Chemical Society. 141, 10, p. 4453-4459 7 p.

    Research output: Contribution to journalArticle

  3. Triggered gate opening and breathing effects during selective CO2 adsorption by merlinoite zeolite

    Georgieva, V. M., Bruce, E. L., Verbraeken, M., Scott, A., Casteel, W., Brandani, S. & Wright, P. A., 2 Aug 2019, In : Journal of the American Chemical Society. Article ASAP

    Research output: Contribution to journalReview article

  4. Two synthetic replicators compete to process a dynamic reagent pool

    Kosikova, T. & Philp, D., 20 Feb 2019, In : Journal of the American Chemical Society. 141, 7, p. 3059-3072

    Research output: Contribution to journalArticle

ID: 257497955