Local structures of rare earth phosphate minerals by NMR Show others and affiliations
2022 (English) In: Journal of Solid State Chemistry, ISSN 0022-4596, E-ISSN 1095-726X, Vol. 311, article id 123097Article in journal (Refereed) Published
Abstract [en]
31 P 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 31 P 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.
Place, publisher, year, edition, pages Elsevier, 2022. Vol. 311, article id 123097
Keywords [en]
Rare earth phosphate structure, 31P solid state NMR, DFT calculations, Surface hydration
National Category
Geochemistry Geology
Research subject Chemistry of Interfaces
Identifiers URN: urn:nbn:se:ltu:diva-90116 DOI: 10.1016/j.jssc.2022.123097 ISI: 000832420000001 Scopus ID: 2-s2.0-85128236902 OAI: oai:DiVA.org:ltu-90116 DiVA, id: diva2:1650666
Funder EU, Horizon 2020, 713606 Swedish Research Council Formas, 2018-00630
Note Validerad;2022;Nivå 2;2022-04-20 (hanlid);
Funder: Universityof Oulu (Kvantum Institute); Academy of Finland (285666, 289649, 294027, 319216)
2022-04-082022-04-082022-11-16 Bibliographically approved