Structural Characterization of the New Fullerene-Rare Gas Compound Ar1C60

We communicate how C₆₀ Hot Isostatically Pressed (HIPed) at 200° or 400°C with a pressure of 1.7 kbar of Ar produces the new fullerene-rare gas compound Ar₁C₆₀. We have shown, using Xray powder diffraction and subsequent Rietveld analysis, that this solid can be characterised stoichiometrically as Ar₁C_60- The stoichiometry has also been confirmed by thermal gravimetric analysis (TGA) showing 5% by weight to be Ar (expected=5.25%). The presence of Ar is confirmed by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). This material is found to be remarkably stable to loss of Ar over several weeks at room temperature. This represents the first full characterisation of an interstitial rare gas fullerene compound.