Stable Compounds of Helium and Neon: He@C60 and Ne@C60

@article{Saunders1993StableCO,
  title={Stable Compounds of Helium and Neon: He@C60 and Ne@C60},
  author={Martin. Saunders and Hugo A. Jim�nez-V�zquez and R. James Cross and Robert J. Poreda},
  journal={Science},
  year={1993},
  volume={259},
  pages={1428 - 1430}
}
It is demonstrated that fullerenes, prepared via the standard method (an arc between graphite electrodes in a partial pressure of helium), on heating to high temperatures release 4He and 3He. The amount corresponds to one 4He for every 880,000 fullerene molecules. The 3He/4He isotopic ratio is that of tank helium rather than that of atmospheric helium. These results convincingly show that the helium is inside and that there is no exchange with the atmosphere. The amount found corresponds with a… 

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