https://pubs.rsc.org/en/content/articlelanding/2010/cc/c0cc00113a
Rational synthesis, enrichment, and 13C NMR spectra of endohedral C60 and C70 encapsulating a...
Endohedral fullerenes encapsulating a helium atom, i.e., He@C60 and He@C70, at occupation levels of 30% were prepared by rational chemical synthesis. The...