Abstract
Experimental measurements of 19 F isotropic chemical shifts on a large set of mainly ionic fluoride compounds (from simple metal fluorides to transition metal fluoride glasses) obtained by MAS NMR at 15 kHz spinning rate are simultaneously investigated. First, Ramsey's theory of the chemical shift with molecular orbitals obtained by Lödwin's orthogonalisation method is used to evaluate the isotropic part of the 19 F chemical shift in ionic fluorides for which the crystallographic structure and the atomic radial wavefunctions are known. Then, assuming that the paramagnetic part of the 19 F shielding in a given material is simply the summation of the paramagnetic contributions due to all the cations in the neighbourhood of the considered fluorine, a superposition model of the 19 F isotropic chemical shift is developed. Finally, this empirical approach is applied to complex fluoride compounds of unknown structure and it is demonstrated that it allows to obtain reliable structural informations. More generally, it can be applied to all the ionic fluorides.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
