This article does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (December 2009)

Diacetylene
Other names	1,3-butadiyne, buta-1,3-diyne, biacetylene, butadiyne
Identifiers
CAS number	460-12-8 Y
PubChem	9997
SMILES	C#CC#C
Properties
Molecular formula	C4H2
Molar mass	50.046 g/mol
Appearance	Gas
Melting point	-10 °C
Boiling point	10 °C
Hazards
R-phrases	R11 R19
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Diacetylene (also known as butadiyne), with the formula C₄H₂, is a highly unsaturated hydrocarbon that contains one single bond and two triple bonds. It is the first in the series of polyynes.

[edit] Occurrence in nature

Diacetylene has been identified in the atmosphere of Titan and in the protoplanetary nebula CRL 618 by its characteristic vibrational modes. The molecule is most likely to have formed in Titan's atmosphere by a reaction between acetylene and the ethynyl radical C₂H, which is produced when acetylene undergoes photolysis. This radical can in turn attack the triple bond in acetylene and react efficiently even at cold temperatures.

[edit] See also

• Acetylene
• Hydrocarbon