19F/23Na Double Resonance MAS NMR Study of Oxygen/Fluorine Ordering in the Oxyfluoride Na5W3O9F5

• Published in: Chemistry of materials 2000-12, Vol.12 (12), p.3611-3616
• Main Authors: Du, Lin-Shu, Samoson, Ago, Tuherm, Tiit, Grey, Clare P
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Double nuclear magnetic resonance (dnmr), dynamical nuclear polarization; Exact sciences and technology; Inorganic compounds; Magnetic double resonances and cross effects; Magnetic resonances and relaxations in condensed matter, mössbauer effect; Physics; Structure of solids and liquids; crystallography; Structure of specific crystalline solids
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/cm000355h

Three resonances corresponding to the three crystallographically distinct fluorine sites were resolved in the high-resolution 19F MAS spectrum of chiolite (Na5Al3F14) collected at a field strength of 19.6 T and at a spinning speed of 40 kHz. In contrast, only one broad resonance is observed in the 19F MAS NMR spectrum of the isostructural compound Na5W3O9F5. Thus, a combination of 19F MAS, 19F → 23Na CP, and 23Na → 19F HETCOR NMR experiments was required to resolve the resonances from the different local environments in this compound. Fluorine was shown to preferentially occupy two of the three anion sites.