Editing Fullerene (section)

===Stability===
Two theories have been proposed to describe the molecular mechanisms that make fullerenes. The older, "bottom-up" theory proposes that they are built atom-by-atom. The alternative "top-down" approach claims that fullerenes form when much larger structures break into constituent parts.<ref name="kurz">[http://www.kurzweilai.net/support-for-top-down-theory-of-how-buckyballs-form Support for top-down theory of how 'buckyballs’ form]. kurzweilai.net. 24 September 2013</ref>

In 2013 researchers discovered that asymmetrical fullerenes formed from larger structures settle into stable fullerenes. The synthesized substance was a particular [[metallofullerene]] consisting of 84 carbon atoms with two additional carbon atoms and two [[yttrium]] atoms inside the cage. The process produced approximately 100 micrograms.<ref name=kurz/>

However, they found that the asymmetrical molecule could theoretically collapse to form nearly every known fullerene and metallofullerene. Minor perturbations involving the breaking of a few molecular bonds cause the cage to become highly symmetrical and stable. This insight supports the theory that fullerenes can be formed from graphene when the appropriate molecular bonds are severed.<ref name=kurz/><ref>{{Cite journal |last1=Zhang |first1=J. |last2=Bowles |first2=F. L. |last3=Bearden |first3=D. W. |last4=Ray |first4=W. K. |last5=Fuhrer |first5=T. |last6=Ye |first6=Y. |last7=Dixon |first7=C. |last8=Harich |first8=K. |last9=Helm |first9=R. F. |last10=Olmstead |first10=M. M. |last11=Balch |first11=A. L. |display-authors=3 |year=2013 |title=A missing link in the transformation from asymmetric to symmetric metallofullerene cages implies a top-down fullerene formation mechanism |journal=Nature Chemistry |volume=5 |issue=10 |pages=880–885 |bibcode=2013NatCh...5..880Z |doi=10.1038/nchem.1748 |pmid=24056346 |last12=Dorn |first12=H. C.}}</ref>