University of Oulu

Khalili, R., Larsson, A.-C., Telkki, V.-V., Lantto, P., & Kantola, A. M. (2022). Local structures of rare earth phosphate minerals by NMR. Journal of Solid State Chemistry, 311, 123097.

Local structures of rare earth phosphate minerals by NMR

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Author: Khalili, Roya1; Larsson, Anna-Carin2; Telkki, Ville-Veikko1;
Organizations: 1NMR Research Unit, University of Oulu, P. O. Box 3000, FI-90014, Oulu, Finland
2Chemistry of Interfaces, Luleå University of Technology, Laboratorievägen 14, SE-97187, Luleå, Sweden
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.2 MB)
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Language: English
Published: Elsevier, 2022
Publish Date: 2022-09-22


31P solid state NMR studies combined with DFT calculations were conducted over a chosen series of rare earth element phosphates (REEPO4s), selected on the basis of the size and magnetic properties of REEs (La, Sm, Lu and Yb). PXRD analysis revealed the presence of rhabdophane (La, Sm), monazite (La) and xenotime (Lu, Yb) phases of these phosphate compounds. The direct excitation and cross-polarization 31P NMR studies together with calculations confirmed the PXRD results for the abovementioned bulk structures, but also revealed presence of several local phosphorus environments on surfaces. NMR is sensitive to the atomic level local interactions, and we were able to show that the combination of experimental and theoretical NMR methods can provide information unavailable with other methods. Due to the distinct coordination of the water molecules to crystal surfaces with different Miller plane cleavages, we were able to identify from the NMR spectra the surface structures of the studied minerals. This adds to the knowledge of the bulk structures of REE phosphates and provides preliminary data for studies on coordination of various ligands on REE phosphate surfaces. This combination of experimental and computational methods can further be used for studies on surface chemistry, important for applications in catalysis and extraction of REEs from the minerals.

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Series: Journal of solid state chemistry
ISSN: 0022-4596
ISSN-E: 1095-726X
ISSN-L: 0022-4596
Volume: 311
Article number: 123097
DOI: 10.1016/j.jssc.2022.123097
Type of Publication: A1 Journal article – refereed
Field of Science: 116 Chemical sciences
114 Physical sciences
Funding: This project has received funding from the University of Oulu (Kvantum Institute) and the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska−Curie (grant agreement no. 713606). We also acknowledge support provided by the Academy of Finland (projects 285666 (P.L.), 289649 (V.-V.T.), 294027 (V.-V.T.) and 319216 (V.-V.T.)) as well as from Formas (project 2018–00630, A.-C.L.). Computational resources due to CSC (Espoo, Finland) and the Finnish Grid and Cloud Infrastructure project (persistent identifier urn:nbn:fi:research-infras-2016072533), were used.
EU Grant Number: (713606) I4FUTURE - Novel Imaging and Characterisation Methods in Bio, Medical, and Environmental Research and Technology Innovations
Academy of Finland Grant Number: 285666
Detailed Information: 285666 (Academy of Finland Funding decision)
289649 (Academy of Finland Funding decision)
294027 (Academy of Finland Funding decision)
319216 (Academy of Finland Funding decision)
Dataset Reference: Supplementary data to this article can be found online at
Copyright information: © 2022 The Authors. This is an open access article under the CC BY license (