The Nuclear Magnetic Shielding of the F-Nuclei in KZnF3
نویسنده
چکیده
Using solid state multiple pulse techniques the magnetic shielding tensors a of the F nuclei in a single crystal of KZnF 3 have been measured. The F~-site symmetry in KZnF3 , D 4 h , allows axial anisotropy of a and determines fully the principal shielding directions. Using CaF 2 as the reference compound, the average shielding is + 85 ppm and the shielding anisotropy is + 18.4 ppm. These results are discussed in terms of shielding contributions from (a) the closed shell electrons of the F~-ion whose shielding is considered, (b) the closed shell electrons of the neighbouring metal and fluorine ions and (c) weak admixture of covalency to the predominantly ionic Zn —F~ bonding.
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