Wikipedia
Dicyanoacetylene
Dicyanoacetylene, also called carbon subnitride or but-2-ynedinitrile ( IUPAC), is a compound of carbon and nitrogen with chemical formula CN. It has a linear molecular structure, N≡C−C≡C−C≡N (often abbreviated as NCN), with alternating triple and single covalent bonds. It can be viewed as acetylene with the two hydrogen atoms replaced by cyanide groups.
At room temperature, dicyanoacetylene is a clear liquid. Because of its high endothermic heat of formation, it can explode to carbon powder and nitrogen gas, and it burns in oxygen with a bright blue-white flame at a temperature of 5260 K (4990 °C, 9010 °F), which is the hottest flame of any known chemical reaction.