Microwave-Assisted Intercalation: Exploring Electronic and Structural Features of Metastable MMo6S8 (M = Ag, Sn)

Abstract

Presented in this work is a synthetic approach for metastable Type I Chevrel phase sulfides, MMo6S8 (M = Ag, Sn), utilizing rapid microwave-assisted medium temperature intercalation. Using X-ray absorption spectroscopy electronic structure and local coordination of sulfur and molybdenum bonding environments are probed as a function of Type I metal intercalant. Intercalant promoter-induced electron donation effects were observed through analysis of the sulfur K-edge pre-edge feature and Mo L3-edge in the X-ray absorption near edge regions. Calculated electron density maps reveal more covalent interactions between Ag and S atoms versus more ionic interactions between Sn and S. Changes to Chevrel phase structure upon intercalation are investigated through Mo K-edge extended X-ray absorption fine structure analysis. Evaluation of Mo-Mo intracluster distances allow for the calculation of cluster anisotropy of Type I CPs with cluster anisotropy as low as 1.84% These findings help elucidate how electronic and local structure can be modulated through intercalation and the importance of cation identity to fine tune structure.