Skip to content

Research at St Andrews

Exploring cation disorder in mixed-metal pyrochlore ceramics using 17O NMR spectroscopy and first-principles calculations

Research output: Contribution to journalArticlepeer-review

DOI

Open Access permissions

Open

Author(s)

Arantxa Fernandes, Robert F Moran, David McKay, Ben Griffiths, Anna Herlihy, Karl R Whittle, Daniel McLean Dawson, Sharon E. Ashbrook

School/Research organisations

Abstract

Characterising the local structures (e.g., the cation distribution) of mixed-metal ceramics by NMR spectroscopy is often challenging owing to the unfavourable properties (low γ, large quadrupole moment and/or low abundance) of many metal nuclei. 17O is an attractive option owing to the prevalence of oxygen within ceramics. The moderate γ and small quadrupole moment of 17O mean that the greatest barrier to accessing the information available from this nucleus is isotopic enrichment. We explore the challenges of ensuring uniform isotopic enrichment with 17O2(g) for the pyrochlore solid solutions, Y2SnxTi2xO7, La2SnxZr2–xO7 and La2SnxHf2xO7, demonstrating that high enrichment temperatures (900 °C for 12 h) are required. In addition, for sites with very high symmetry (such as the tetrahedral OY4 and OLa4 sites with CQ ≈ 0 present here), we demonstrate that quantitative 17O NMR spectra require correction for the differing contributions from the centreband of the satellite transitions, which can be as high as a factor of ~3.89. It is common to use first-principles calculations to aid in interpreting NMR spectra of disordered solids. Here, we use an ensemble modelling approach to ensure that all possible cation arrangements are modelled in the minimum possible number of calculations. By combining uniform isotopic enrichment, quantitative NMR spectroscopy and a comprehensive computational approach, we are able to show that the cation distribution in Y2SnxTi2xO7 is essentially random, whereas in La2SnxZr2xO7 and La2SnxHf2xO7, OLa2SnZr and OLa2SnHf sites are slightly energetically disfavoured, leading to a weak preference for clustering of like cations.
Close

Details

Original languageEnglish
Number of pages14
JournalMagnetic Resonance in Chemistry
VolumeEarly View
Early online date15 Feb 2021
DOIs
Publication statusE-pub ahead of print - 15 Feb 2021

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

View graph of relations

Related by author

  1. Single-step synthesis and interface tuning of core–shell metal–organic framework nanoparticles

    Orr, K. W. P., Collins, S. M., Reynolds, E. M., Nightingale, F., Boström, H. L. B., Cassidy, S. J., Dawson, D. M., Ashbrook, S. E., Magdysyuk, O. V., Midgley, P., Goodwin, A. L. & Yeung, H. H-M., 9 Feb 2021, In: Chemical Science. Advance Article, 9 p.

    Research output: Contribution to journalArticlepeer-review

  2. Thermal dehydrofluorination of GaPO-34 revealed by NMR crystallography

    Dawson, D. M., Macfarlane, L. E., Amri, M., Walton, R. I. & Ashbrook, S. E., 24 Jan 2021, In: Journal of Physical Chemistry C. Articles ASAP

    Research output: Contribution to journalArticlepeer-review

  3. Synthesis of chiral MOF-74 frameworks by post-synthetic modification using an amino acid

    Tanase, S., Gheorghe, A., Dubbeldam, D., Strudwick, B., Woutersen, S., Ashbrook, S. E. & Dawson, D. M., 20 Oct 2020, In: Chemistry - A European Journal. Early View, 10 p.

    Research output: Contribution to journalArticlepeer-review

  4. Site-specific iron substitution in STA-28, a large pore aluminophosphate zeotype prepared using 1,10-phenanthrolines as framework-bound templates

    Watts, A. E., Lozinska, M. M., Slawin, A. M. Z., Mayoral, A., Dawson, D. M., Ashbrook, S. E., Bode, B. E., Dugulan, I., Shannon, M., Cox, P., Turrina, A. & Wright, P. A., 17 Aug 2020, In: Angewandte Chemie International Edition. 59, 35, p. 15186-15190 5 p.

    Research output: Contribution to journalArticlepeer-review

  5. Application of NMR crystallography to highly disordered templated materials: extensive local structural disorder in the gallophosphate GaPO-34A

    Ashbrook, S. E., Dawson, D. M., Gan, Z., Hooper, J. E., Hung, I., Macfarlane, L. E., McKay, D., McLeod, L. K. & Walton, R. I., 4 Aug 2020, In: Inorganic Chemistry. Article ASAP

    Research output: Contribution to journalArticlepeer-review

Related by journal

  1. Magnetic Resonance in Chemistry (Journal)

    Sharon Elizabeth Marie Ashbrook (Member of editorial board)

    2019 → …

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

  2. Magnetic Resonance in Chemistry (Journal)

    Sharon Elizabeth Marie Ashbrook (Guest editor)

    2010

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

Related by journal

  1. Is the 31P chemical shift anisotropy of aluminophosphates a useful parameter for NMR crystallography?

    Dawson, D. M., Moran, R. F., Sneddon, S. & Ashbrook, S. E., May 2019, In: Magnetic Resonance in Chemistry. 57, 5, p. 176-190

    Research output: Contribution to journalArticlepeer-review

  2. A CW-EPR, ENDOR and special TRIPLE resonance study of a novel magnesium ketyl radical

    Murphy, D., McDyre, L., Carter, E., Stasch, A. & Jones, C., 2011, In: Magnetic Resonance in Chemistry. 49, 4, p. 159 - 163

    Research output: Contribution to journalArticlepeer-review

  3. Comparing quantum-chemical calculation methods for structural investigation of zeolite crystal structures by solid-state NMR spectroscopy

    Brouwer, D. H., Moudrakovski, I. L., Darton, R. J. & Morris, R. E., Dec 2010, In: Magnetic Resonance in Chemistry. 48, p. S113-S121 9 p.

    Research output: Contribution to journalArticlepeer-review

ID: 272742886

Top