Cyclo(6)carbon

The correct title of this article is Cyclo[6]carbon. The substitution of any brackets is due to technical restrictions.

Cyclo[6]carbon is an allotrope of carbon with molecular formula C₆. The molecule is a ring of six carbon atoms, connected by alternating double bonds.^[1] It is, therefore, a member of the cyclo[n]carbon family.

Cyclo(6)carbon

Names
Preferred IUPAC name Hexadehydrobenzene
Identifiers
CAS Number	21894-87-1
3D model (JSmol)	Alternating form: Interactive image Cumulene form: Interactive image
PubChem CID	12334440
CompTox Dashboard (EPA)	DTXSID70491042
InChI InChI=1S/C6/c1-2-4-6-5-3-1 N Key: PXCDDPIOUAJVRE-UHFFFAOYSA-N N
SMILES Alternating form: C1#CC#CC#C1 Cumulene form: C1=C=C=C=C=C=1
Properties
Chemical formula	C6
Molar mass	72.066 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

There have been a few attempts to synthesize cyclo[6]carbon, e.g. by pyrolysis of mellitic anhydride,^[2] but without success until 2023, when it was successfully synthesized by atom manipulation of hexachlorobenzene.^[1]

Calculations suggest that the alternative cyclic cumulene structure, called cyclohexahexaene, is the potential energy minimum of the cyclo[6]carbon framework.^[3]

References

1. Xu, Wei; Sun, Luye; Zheng, Wei; Gao, Wenze; Kang, Faming (2023-10-05), On-surface synthesis of anti-aromatic cyclo[12]carbon and aromatic cyclo[6]carbon, doi:10.21203/rs.3.rs-3411973/v1
2. Fields, Ellis K.; Meyerson, Seymour (October 1966). "Arynes by Pyrolysis of Acid Anhydrides". J. Org. Chem. 31 (10): 3307–3309. doi:10.1021/jo01348a046.
3. Zahradník, Rudolf; Hobza, Pavel; Burcl, Rudolf; Andes Hess, B. (October 1994). "Strained unsaturated molecules. Theoretical study of acyclic and cyclic cumulenes and acetylenes". Journal of Molecular Structure: THEOCHEM. 313 (3): 335–349. doi:10.1016/0166-1280(94)85015-1.