annulene

noun

an·nu·lene ˈan-yə-ˌlēn

plural annulenes

chemistry

: any of a class of completely conjugated cyclic hydrocarbons (such as benzene or cyclooctatetraene)

In 1991, a temperate rainforest near Puerto Montt in central Chile yielded a fungus that made annulene, a hydrocarbon that has a history going back to the first formulations of rocket fuel.—

Buzzy Gordon, Americas, 1 Nov. 2007

This class of annulenes, which have few hydrogens and are considered high-energy because of their numerous triple bonds, has also drawn attention as potential precursors to new carbon allotropes.—

Elizabeth Wilson, Chemical & Engineering News, 3 Mar. 1997

Note: Annulenes have the general chemical formula C_nH_n where n is an even number or C_nH_n + 1 if n is an odd number.