The hexatriynyl radical, , is an organic

radical Radical may refer to: Politics and ideology Politics * Radical politics, the political intent of fundamental societal change *Radicalism (historical), the Radical Movement that began in late 18th century Britain and spread to continental Europe an ...

molecule consisting of a linear chain of six

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon makes ...

atoms terminated by a

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...

(). The

unpaired electron In chemistry, an unpaired electron is an electron that occupies an orbital of an atom singly, rather than as part of an electron pair. Each atomic orbital of an atom (specified by the three quantum numbers n, l and m) has a capacity to contai ...

is located at the opposite end to the hydrogen atom, as indicated. Both experimental work and computer simulations on this species was done in the early 1990s.

Synthesis of the radical

The radical can be synthesized by

photolysis Photodissociation, photolysis, photodecomposition, or photofragmentation is a chemical reaction in which molecules of a chemical compound are broken down by photons. It is defined as the interaction of one or more photons with one target molecule. ...

. Two different examples involve * Argon gas and

buta-1,3-diene 1,3-Butadiene () is the organic compound with the formula (CH2=CH)2. It is a colorless gas that is easily condensed to a liquid. It is important industrially as a precursor to synthetic rubber. The molecule can be viewed as the union of two viny ...

in a mole ratio of 1500:1 * Argon gas and

acetylene Acetylene ( systematic name: ethyne) is the chemical compound with the formula and structure . It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is unstable in its pur ...

in a mole ratio of 100:1

Hexatriyne anion

In 2006 the negatively charged hexatriyne anion of this molecule, C₆H⁻, was the first negatively charged ion to be discovered to exist in the

interstellar medium In astronomy, the interstellar medium is the matter and radiation that exist in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, as well as dust and cosmic rays. It fills interstella ...

, using the

Green Bank Telescope The Robert C. Byrd Green Bank Telescope (GBT) in Green Bank, West Virginia, US is the world's largest fully steerable radio telescope, surpassing the Effelsberg 100-m Radio Telescope in Germany. The Green Bank site was part of the National Rad ...

. Negative ions were thought to be unstable in this environment due to the prevalence of

ultraviolet light Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiati ...

, which dislodges extra electrons such as this.

Synthesis of the anion

The laboratory synthesis starts from

C₂H₂. The reaction takes place within a DC discharge at reduced pressure in a mixture with 15%

argon Argon is a chemical element with the symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third-most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as a ...

. The product is observed by millimeter-wave spectroscopy.

Analogous species

The two species C₄H⁻ and C₈H⁻ have also been detected.

Synthesis of the radical

Hexatriyne anion

Synthesis of the anion

Analogous species

References

See also