NMR in Chevrel-phase solid solution Mo6Se8-xTex

The Mo6Se8-Mo6Te8 solid solution was studied by X-ray diffraction, magnetic susceptibility and Se-77 and Te-125 NMR. Dynamic studies show that substit ution occurs differently when Se replaces Te in Mo6Te8 than when Te replace s Se in Mo6Se8. Selenium first fills the high-symmetry sites and then it be comes statistically distributed on the 6f positions of the R (3) over bar s ymmetry. In the second case, Te occupies randomly the 8 X sites of the Mo6X 8 structure, creating large perturbations of the Te-125 NMR spectra over th e whole range of x. (C) 1999 Elsevier Science B.V. All rights reserved.