Magnetic Shielding of 19F in XeF2

The rigid-lattice second moment of the ¹⁹F nuclear magnetic resonance of XeF₂ has been measured as a function of the external magnetic field. The experimental shielding anisotropy | Δσ | = 105 ± 10 × 10^-6 does not agree closely with a value of σ⊥ - σ‖ = - 506 × 10^-6 previously calculated using a localized orbital model. The field-independent rigid-lattice second moment is ∼ 0.4 G² larger than that calculated from crystallographic data, probably because of large amplitude vibrations in XeF₂. The temperature dependences of the second moment and of the spin-lattice relaxation time are also reported.