Editing Buckminsterfullerene (section)

===Cycloadditions===
The [[Diels–Alder reaction]] is commonly employed to functionalize C<sub>60</sub>. Reaction of C<sub>60</sub> with appropriate substituted diene gives the corresponding adduct.

The Diels–Alder reaction between C<sub>60</sub> and 3,6-diaryl-1,2,4,5-tetrazines affords C<sub>62</sub>. The C<sub>62</sub> has the structure in which a four-membered ring is surrounded by four six-membered rings.

[[File:3D structure of C62 derivative from C60 update.jpg|thumb|A C<sub>62</sub> derivative [C<sub>62</sub>(C<sub>6</sub>H<sub>4</sub>-4-Me)<sub>2</sub>] synthesized from C<sub>60</sub> and 3,6-bis(4-methylphenyl)-3,6-dihydro-1,2,4,5-tetrazine]]

The C<sub>60</sub> molecules can also be coupled through a [2+2] [[cycloaddition]], giving the dumbbell-shaped compound C<sub>120</sub>. The coupling is achieved by high-speed vibrating milling of C<sub>60</sub> with a catalytic amount of [[potassium cyanide|KCN]]. The reaction is reversible as C<sub>120</sub> dissociates back to two C<sub>60</sub> molecules when heated at {{convert|450|K}}. Under high pressure and temperature, repeated [2+2] cycloaddition between C<sub>60</sub> results in polymerized fullerene chains and networks. These polymers remain stable at ambient pressure and temperature once formed, and have remarkably interesting electronic and magnetic properties, such as being [[ferromagnetism|ferromagnetic]] above room temperature.<ref name="InorgChem" />