Cd-113 MAS NMR study of several crystalline fluorides and chlorides containing Cd2+ and 50CdF(2) center dot 30NaCl center dot (20-x) BaF2 center dot xBaCl(2) glasses

摘要

Cd-113 magic-angle spinning nuclear magnetic resonance spectra of crystalline CdF2, KCdF3 and CdCl2 with known crystal structures and vitreous 50CdF(2). 30NaCl . (20 - x)BaF2. xBaCl(2) in mol% (x : 0, 5, 10, 15 and 20) were measured to reveal the anion-coordination environments around Cd2+ in the glasses. The isotropic chemical shifts, delta (iso) of the CdF2, KCdF3 and CdCl2 crystals locate around -226, -105 and 183 ppm, being assigned to the CdF8,CdF6, and CdCl6 polyhedra, respectively. From an analysis of the Cd-113 magic-angle spinning nuclear magnetic resonance spectra of the glasses we deduced that CdFmCln polyhedra (m not equal 0 and n not equal 0) which have not been found in crystalline compounds are present in the glasses. The peak positions and the full widths at half maxima (FWHM) in the glasses increased as BaF2 was replaced by BaCl2. This increase implies that the number of Cl- bonded to Cd2+ increases with increasing BaCl2 content and also that a variety of anion-coordination environments around Cd2+ are more distributed with increasing BaCl2-content. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 7]