⁶³Cu magic angle spinning (MAS) nuclear magnetic resonance (NMR) study of CuX crystals (X = Cl, Br, and I) and CuX-based glasses (X = Cl, Br, and I)

⁶³Cu MAS NMR spectra of CuX crystals (X = Cl, Br, and I) and CuX-based glasses (X = Cl, Br, and I) have been measured. The CuCl and CuI crystals gave the isotropic chemical shift values around 0 ppm, and the CuBr crystal, around -55 ppm. The peak positions of the chlorocuprate(I), bromocuprate(I), and iodocuprate(I) glasses were very close to those of the CuX crystals, respectively. This result indicates that these glasses mainly consist of CuX₄ tetrahedra (X = Cl, Br, and I). The halogen coordination environments around Cu⁺ in bromochlorocuprate(I) glasses were dependent on the kind of modifying cation and the Br^-/(Cl^- + Br^-) ratio. The bromochlorocuprate(I) glasses were mainly composed of CuCl_mBr_4-m or CuCl_nBr_4-n tetrahedra (m = 0, 1, 2, and 4; n = 0, 1, and 4).