Mancude (i.e. having formally the maximum number of noncumulative double bonds) monocyclic hydrocarbon without side chains of the general formula CnHn (n is an even number) or CnHn+1 (n is an odd number). Note that in systematic nomenclature an annulene with seven or more carbon atoms may be named [n]annulene, where n is the number of carbon atoms, e.g. [9]annulene for cyclonona-1,3,5,7-tetraene. IUPAC CLASS NAMES (1993). See aromatic, Hückel (4n + 2) rule.