¹¹³Cd MAS NMR study of several crystalline fluorides and chlorides containing Cd²⁺ and 50CdF₂ · 30NaCl · (20 - x)BaF₂ · xBaCl₂ glasses

¹¹³Cd magic-angle spinning nuclear magnetic resonance spectra of crystalline CdF₂, KCdF₃ and CdCl₂ with known crystal structures and vitreous 50CdF₂ · 30NaCl · (20 - x)BaF₂ · xBaCl₂ 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, δ_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 ¹¹³Cd magic-angle spinning nuclear magnetic resonance spectra of the glasses we deduced that CdF_mCl_n polyhedra (m ≠ 0 and n ≠ 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.