Editing Fullerene (section)

===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.