page_title: Annulene
hierarchical_section_title: Annulene
caption_attribution_description: (left) Chemical structure of triangular dehydrobenzo[12]annulene (tDBA); (right) high-resolution AFM image of tDBA on Ag(111). Inset shows the STM topography. Measurement parameters: Vtip=0 mV and A=60 pm in b and Vtip=−200 mV and I=1 pA in (inset). Scale bar, 500 pm.
context_page_description: Annulenes are monocyclic hydrocarbons that contain the maximum number of non-cumulated double bonds. They have the general formula CₙHₙ or CₙHₙ₊₁. The IUPAC naming conventions are that annulenes with 7 or more carbon atoms are named as [n]annulene, where n is the number of carbon atoms in their ring, though sometimes the smaller annulenes are referred to using the same notation, and benzene is sometimes referred to simply as annulene.
  The first three even annulenes are cyclobutadiene, benzene, and cyclooctatetraene. Some annulenes, namely cyclobutadiene, cyclodecapentaene, cyclododecahexaene and cyclotetradecaheptaene, are unstable, with cyclobutadiene extremely so.
  In the related annulynes, one double bond is replaced by a triple bond.
context_section_description: Annulenes are monocyclic hydrocarbons that contain the maximum number of non-cumulated double bonds ('mancude'). They have the general formula CₙHₙ (when n is an even number) or CₙHₙ₊₁ (when n is an odd number). The IUPAC naming conventions are that annulenes with 7 or more carbon atoms are named as [n]annulene, where n is the number of carbon atoms in their ring, though sometimes the smaller annulenes are referred to using the same notation, and benzene is sometimes referred to simply as annulene.
  The first three even annulenes are cyclobutadiene, benzene, and cyclooctatetraene ([8]annulene). Some annulenes, namely cyclobutadiene, cyclodecapentaene ([10]annulene), cyclododecahexaene ([12]annulene) and cyclotetradecaheptaene ([14]annulene), are unstable, with cyclobutadiene extremely so.
  In the related annulynes, one double bond is replaced by a triple bond.
caption: Structure and AFM image of dehydrobenzo[12]annulene
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