Structure Analysis of Metal(I) Halides Mixed Crystal by 63Cu MAS NMR and X-Ray Diffraction Methods. I. CuxAg1−xI Crystal

63Cu MAS NMR and X-ray diffraction methods have been used to perform a structure analysis of mixed crystals, CuxAg1−xI. The mixed crystals were prepared and analyzed as a complete solid-solution and a core-shell type of crystal by the X-ray diffraction method. 63Cu signals in the complete solid-solution shifted with broadening to a high field around 14–33 ppm relative to solid CuI, as the silver/copper ratio increased. The line width of the signal was 2-to 2.5-times as broad as that for solid CuI. On the othe hand, the signal in a core-shell type of crystal did not shift much and the line width was much the same as that for CuI. The shifts and broad line widths in the complete solid-solution can be explained by considering components which involve the second-order quadrupolar coupling tensors. The quadrupolar coupling tensors are seen to be caused by changing from Td of –(CuI4)–spcies to its C3v and C2v symmetries due to replacing Cu with Ag in the crystal.