NMR-spectroscopic study of 207Pb in pure and barium diluted lead phosphate.
31P and 207Pb MAS and static 207Pb NMR spectra of Pb3(PO4)2 and (Pb1-xBa(x))3(PO4)2 (x = 0.08, 0.12) are analysed. The resonances stemming from different cation sites are correlated with the corresponding local symmetry and their oxygen neighbours. The coordination sphere of Pb(1) consists of 12 oxygen atoms and shows characteristics of a near-axial arrangement with a comparatively low anisotropy. The tenfold coordinated Pb(2) atoms are located in a more anisotropically-coordinated site. In Pb-diluted lead phosphate crystals the Pb(2) positions appear to be preferentially substituted by barium. There are indications that the cation distributions in the diluted samples are inhomogeneous. Furthermore, 31P MAS NMR experiments indicate a single phosphorus position.
Institut für Mineralogie, Universität Hannover, Germany. m.fechtelkord@mbox.mineralogie.uni-hannover.de
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Fechtelkord
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Bismayer
D016880:Anisotropy; D001464:Barium; D006801:Humans; D007554:Isotopes; D007854:Lead / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*
D007554:Isotopes; D001464:Barium; D007854:Lead; C036682:lead phosphate