Editing Fullerene (section)

==Reactions==

===Polymerization===
Under high pressure and temperature, buckyballs collapse to form various one-, two-, or three-dimensional carbon frameworks. Single-strand polymers are formed using the Atom Transfer Radical Addition Polymerization (ATRAP) route.<ref>{{Cite journal |last1=Hiorns |first1=R.C. |last2=Cloutet, Eric |last3=Ibarboure |first3=Emmanuel |last4=Khoukh |first4=Abdel |last5=Bejbouji |first5=Habiba |last6=Vignau |first6=Laurence |last7=Cramail |first7=Henri |display-authors=3 |year=2010 |title=Synthesis of Donor-Acceptor Multiblock Copolymers Incorporating Fullerene Backbone Repeat Units |journal=Macromolecules |series=14 |volume=43 |issue=14 |pages=6033–6044 |bibcode=2010MaMol..43.6033H |doi=10.1021/ma100694y}}</ref>

[[Aggregated diamond nanorod|"Ultrahard fullerite"]] is a coined term frequently used to describe material produced by high-pressure high-temperature (HPHT) processing of fullerite. Such treatment converts fullerite into a nanocrystalline form of [[diamond]] which has been reported to exhibit remarkable mechanical properties.<ref>{{Cite journal |last1=Blank |first1=V. |last2=Popov |first2=M. |last3=Pivovarov |first3=G. |last4=Lvova |first4=N. |last5=Gogolinsky |first5=K. |last6=Reshetov |first6=V. |display-authors=3 |year=1998 |title=Ultrahard and superhard phases of fullerite {{chem|C|60}}: Comparison with diamond on hardness and wear |journal=Diamond and Related Materials |volume=7 |issue=2–5 |pages=427–431 |bibcode=1998DRM.....7..427B |citeseerx=10.1.1.520.7265 |doi=10.1016/S0925-9635(97)00232-X}}</ref>
[[Image:C60 SEM.jpg|thumb|Fullerite ([[scanning electron microscope]] image)]]

===Chemistry===
{{Main|Fullerene chemistry}}

Fullerenes are stable, but not totally unreactive. The sp<sup>2</sup>-hybridized carbon atoms, which are at their energy minimum in planar [[graphite#Structure|graphite]], must be bent to form the closed sphere or tube, which produces [[Ring strain|angle strain]]. The characteristic reaction of fullerenes is [[electrophilic addition]] at 6,6-double bonds, which reduces angle strain by changing sp<sup>2</sup>-hybridized carbons into sp<sup>3</sup>-hybridized ones. The change in hybridized [[atomic orbital|orbital]]s causes the bond angles to decrease from about 120° in the sp<sup>2</sup> orbitals to about 109.5° in the sp<sup>3</sup> orbitals. This decrease in bond angles allows for the bonds to bend less when closing the sphere or tube, and thus, the molecule becomes more stable.

===Solubility===
{{main|Fullerene solubility}}
[[File:C60 Fullerene solution.jpg|thumb|{{chem|C|60}} in solution]]

[[File:Carbon 60 Olive Oil Solution.JPG|thumb|{{chem|C|60}} in extra virgin olive oil, showing the characteristic purple color of pristine {{chem|C|60}} solutions]]

Fullerenes are soluble in many organic [[solvent]]s, such as [[toluene]], [[chlorobenzene]], and [[1,2,3-trichloropropane]]. Solubilities are generally rather low, such as 8 g/L for C<sub>60</sub> in [[carbon disulfide]]. Still, fullerenes are the only known [[allotrope]] of carbon that can be dissolved in common solvents at room temperature.<ref>{{Cite journal |last1=Beck |first1=Mihály T. |last2=Mándi |first2=Géza |year=1997 |title=Solubility of {{chem|C|60}} |journal=Fullerenes, Nanotubes and Carbon Nanostructures |volume=5 |issue=2 |pages=291–310 |doi=10.1080/15363839708011993}}</ref><ref>{{Cite journal |last1=Bezmel'nitsyn |first1=V.N. |last2=Eletskii |first2=A.V. |last3=Okun' |first3=M.V. |year=1998 |title=Fullerenes in solutions |journal=[[Physics-Uspekhi]] |volume=41 |issue=11 |pages=1091–1114 |bibcode=1998PhyU...41.1091B |doi=10.1070/PU1998v041n11ABEH000502 |s2cid=250785669}}</ref><ref>{{Cite journal |last1=Ruoff |first1=R.S. |last2=Tse, Doris S. |last3=Malhotra |first3=Ripudaman |last4=Lorents |first4=Donald C. |year=1993 |title=Solubility of fullerene ({{chem|C|60}}) in a variety of solvents |url=http://bucky-central.me.utexas.edu/RuoffsPDFs/40.pdf |url-status=dead |journal=[[Journal of Physical Chemistry]] |volume=97 |issue=13 |pages=3379–3383 |doi=10.1021/j100115a049 |archive-url=https://web.archive.org/web/20120508111820/http://bucky-central.me.utexas.edu/RuoffsPDFs/40.pdf |archive-date=8 May 2012 |access-date=24 February 2015}}</ref><ref>{{Cite journal |last1=Sivaraman |first1=N. |last2=Dhamodaran |first2=R. |last3=Kaliappan |first3=I. |last4=Srinivasan |first4=T. G. |last5=Vasudeva Rao |first5=P. R. P. |last6=Mathews |first6=C. K. C. |display-authors=3 |year=1994 |title=Solubility of {{chem|C|70}} in Organic Solvents |journal=Fullerene Science and Technology |volume=2 |issue=3 |pages=233–246 |doi=10.1080/15363839408009549}}</ref><ref>{{Cite journal |last1=Semenov |first1=K. N. |last2=Charykov |first2=N. A. |last3=Keskinov |first3=V. A. |last4=Piartman |first4=A. K. |last5=Blokhin |first5=A. A. |last6=Kopyrin |first6=A. A. |display-authors=3 |year=2010 |title=Solubility of Light Fullerenes in Organic Solvents |journal=Journal of Chemical & Engineering Data |volume=55 |pages=13–36 |doi=10.1021/je900296s}}</ref> Among the best solvents is [[1-chloronaphthalene]], which will dissolve 51 g/L of C<sub>60</sub>.

Solutions of pure buckminsterfullerene have a deep purple color. Solutions of {{chem|C|70}} are a reddish brown. The [[higher fullerenes]] {{chem|C|76}} to {{chem|C|84}} have a variety of colors.

Millimeter-sized crystals of {{chem|C|60}} and {{chem|C|70}}, both pure and solvated, can be grown from benzene solution. Crystallization of {{chem|C|60}} from benzene solution below 30&nbsp;°C (when solubility is maximum) yields a [[triclinic]] solid [[solvate]] {{chem|C|60}}·4{{chem|C|6|H|6}}. Above 30&nbsp;°C one obtains solvate-free [[face-centered cubic|fcc]] {{chem|C|60}}.<ref>{{Cite journal |last=Talyzin |first=A.V. |year=1997 |title=Phase Transition {{chem|C|60}}−{{chem|C|60}}*4{{chem|C|6|H|6}} in Liquid Benzene |journal=[[Journal of Physical Chemistry B]] |volume=101 |issue=47 |pages=9679–9681 |doi=10.1021/jp9720303}}</ref><ref>{{Cite journal |last1=Talyzin |first1=A.V. |last2=Engström |first2=I. |year=1998 |title={{chem|C|70}} in Benzene, Hexane, and Toluene Solutions |journal=[[Journal of Physical Chemistry B]] |volume=102 |issue=34 |pages=6477–6481 |doi=10.1021/jp9815255}}</ref>

===Quantum mechanics===
In 1999, researchers from the [[University of Vienna]] demonstrated that [[wave-particle duality]] applied to molecules such as fullerene.<ref>{{Cite journal |last1=Arndt |first1=M. |last2=Nairz, Olaf |last3=Vos-Andreae |first3=Julian |last4=Keller |first4=Claudia |last5=Van Der Zouw |first5=Gerbrand |last6=Zeilinger |first6=Anton |display-authors=3 |year=1999 |title=Wave-particle duality of {{chem|C|60}} |url=http://www.qudev.ethz.ch/phys4/studentspresentations/waveparticle/arndt_c60molecules.pdf |journal=[[Nature (journal)|Nature]] |volume=401 |issue=6754 |pages=680–2 |bibcode=1999Natur.401..680A |doi=10.1038/44348 |pmid=18494170 |s2cid=4424892}}</ref>

===Superconductivity===
{{main|Buckminsterfullerene}}
Fullerenes are normally electrical insulators, but when crystallized with alkali metals, the resultant compound can be conducting or even superconducting.<ref>{{Cite book |last=Katz, E. A. |title=Nanostructured materials for solar energy conversion |publisher=Elsevier |year=2006 |isbn=978-0-444-52844-5 |editor-last=Sōga, Tetsuo |pages=372, 381 |chapter=Fullerene Thin Films as Photovoltaic Material |chapter-url=https://books.google.com/books?id=GmQR1tuk5IgC&pg=PA361}}</ref>

===Chirality===
Some fullerenes (e.g. {{chem|C|76}}, {{chem|C|78}}, {{chem|C|80}}, and {{chem|C|84}}) are [[inherent chirality|inherently chiral]] because they are D<sub>2</sub>-symmetric, and have been successfully resolved. Research efforts are ongoing to develop specific sensors for their enantiomers.

===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>