Cyclooctadeca-1,3,5,7,9,11,13,15,17-nonayne or cyclo 8arbon is an

allotrope of carbon Carbon is capable of forming many allotropes (structurally different forms of the same element) due to its valency ( tetravalent). Well-known forms of carbon include diamond and graphite. In recent decades, many more allotropes have been disc ...

with

molecular formula A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as paren ...

. The molecule is a

ring (The) Ring(s) may refer to: * Ring (jewellery), a round band, usually made of metal, worn as ornamental jewelry * To make a sound with a bell, and the sound made by a bell Arts, entertainment, and media Film and TV * ''The Ring'' (franchise), a ...

of eighteen

carbon Carbon () is a chemical element; it has chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 ...

atoms, connected by alternating

triple Triple is used in several contexts to mean "threefold" or a " treble": Sports * Triple (baseball), a three-base hit * A basketball three-point field goal * A figure skating jump with three rotations * In bowling terms, three strikes in a row * I ...

and

single bond In chemistry, a single bond is a chemical bond between two atoms involving two valence electrons. That is, the atoms share one pair of electrons where the bond forms. Therefore, a single bond is a type of covalent bond. When shared, each of th ...

s; thus, it is a

polyyne A polyyne is any organic compound with alternating Single bond, single and triple bonds; that is, a series of consecutive alkynes, with ''n'' greater than 1. These compounds are also called polyacetylenes, especially in the natural products and ...

and a

cyclocarbon In organic chemistry, a cyclo 'n''arbon (or simply cyclocarbon) is a chemical compound consisting solely of a number ''n'' of carbon atoms covalently linked in a ring. Since the compounds are composed only of carbon atoms, they are allotropes of ...

. Cyclo 8arbon is the smallest cyclo 'n''arbon predicted to be relatively stable, with a computed

strain energy In physics, the elastic potential energy gained by a wire during elongation with a tensile (stretching) or compressive (contractile) force is called strain energy. For linearly elastic materials, strain energy is: : U = \frac 1 2 V \sigma \v ...

of 72 kilocalories per mole. A collaboration of teams at

IBM International Business Machines Corporation (using the trademark IBM), nicknamed Big Blue, is an American Multinational corporation, multinational technology company headquartered in Armonk, New York, and present in over 175 countries. It is ...

and the

University of Oxford The University of Oxford is a collegiate university, collegiate research university in Oxford, England. There is evidence of teaching as early as 1096, making it the oldest university in the English-speaking world and the List of oldest un ...

team claimed to synthesize it in solid state in 2019 by

electrochemical Electrochemistry is the branch of physical chemistry concerned with the relationship between electrical potential difference and identifiable chemical change. These reactions involve electrons moving via an electronically conducting phase (typi ...

decarbonylation In chemistry, decarbonylation is a type of organic reaction that involves the loss of carbon monoxide (CO). It is often an undesirable reaction, since it represents a degradation. In the chemistry of metal carbonyls, decarbonylation describes a ...

of several sites of a

cyclobutanone Cyclobutanone is an organic compound with molecular formula (CH2)3CO. It is a four-membered cyclic ketone (cycloalkanone). It is a colorless volatile liquid at room temperature. Since cyclopropanone is highly sensitive, cyclobutanone is the smalle ...

structure: Later, researchers from Spain have used computational techniques to probe the structural and electronic properties of the molecule, and have discovered it to be an electron acceptor. Synthese C18

According to these IBM researchers, the

electronic structure Quantum chemistry, also called molecular quantum mechanics, is a branch of physical chemistry focused on the application of quantum mechanics to chemical systems, particularly towards the quantum-mechanical calculation of electronic contributions ...

of their product consists of alternating

triple bond A triple bond in chemistry is a chemical bond between two atoms involving six Electron pair bond, bonding electrons instead of the usual two in a covalent bond, covalent single bond. Triple bonds are stronger than the equivalent covalent bond, sin ...

s and

s, rather than a

cumulene A cumulene is a compound having three or more ''cumulative'' (consecutive) double bonds. They are analogous to allenes, only having a more extensive chain. The simplest molecule in this class is butatriene (), which is also called simply ''cumu ...

-type structure of consecutive

double bond In chemistry, a double bond is a covalent bond between two atoms involving four bonding electrons as opposed to two in a single bond. Double bonds occur most commonly between two carbon atoms, for example in alkenes. Many double bonds exist betw ...

s. This supposedly makes this molecule a

semiconductor A semiconductor is a material with electrical conductivity between that of a conductor and an insulator. Its conductivity can be modified by adding impurities (" doping") to its crystal structure. When two regions with different doping level ...

References

{{Allotropes of carbon Aromatic compounds Group IV semiconductors Polyynes Cyclocarbons Substances discovered in the 2010s Cycloalkynes