Double bonds, carbon allotropes

Robert Curl, Richard Smalley, and Harold Kroto were awarded the Nobel prize in chemistry in 1996 for the discovery of the soccer-ball-shaped molecule C60. This fundamental molecule was the first of a new series of molecular allotropes of carbon. The enthalpy of combustion of C60 is —25 937 kj-mol, and its enthalpy of sublimation is +233 kj-mol There are 90 bonds in C60, of which 60 are single bonds and 30 are double bonds. Like benzene, C60 has... 

Ozone, O3, is an allotrope of oxygen that adds rapidly to carbon-carbon double bonds, which is followed by reductive or oxidative cleavage. 

Linear carbon chains with sp hybridization have been proposed to be present in the interstellar medium [2-4]. These chains can be constituted by alternate single (C-C) and triple (C=C) bonds (polyynes) or double (C=C) bonds (poly-cumulenes) and have been proposed as building blocks for carbynes, a carbon allotrope [5],... 

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