The nuclear magnetic resonance of 129Xe trapped in clathrates and some other solids

Abstract

¹²⁹ Xe NMR spectra were obtained for xenon trapped in the cages of clathrate hydrates and a clathrasil sample. The data, together with shift data for solid xenon, have yielded a linear correlation between the radius of the free space available to the xenon atom and the chemical shift. This observation cannot be rationalized by using simple binary collision theory. In order to account for the observation of anisotropic chemical shifts for xenon trapped in non-spherical environments a simple multiple-site model was developed. Several applications of ¹²⁹Xe NMR spectroscopy are also presented. These include the identification of new clathrate hydrates, the use of ¹²⁹Xe NMR to follow changes in site symmetry in a clathrasil and a cyclodextrin inclusion compound, and the observation of trapping sites in crystalline and amorphous solids.