Dicyanoacetylene
| Names | |
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| Preferred IUPAC name
But-2-ynedinitrile | |
Other names
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| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
PubChem CID |
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CompTox Dashboard (EPA) |
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| Properties | |
| C4N2 | |
| Molar mass | 76.058 g·mol−1 |
| Appearance | Colorless volatile liquid |
| Odor | Strong |
| Density | 0.907 g/cm3 |
| Melting point | 20.5 °C (68.9 °F; 293.6 K) |
| Boiling point | 76.5 °C (169.7 °F; 349.6 K) |
| Solubility | Soluble in organic solvents |
| Thermochemistry | |
Heat capacity (C) |
77.6017 J/(mol·K) |
Std enthalpy of formation (ΔfH⦵298) |
+500.4 kJ/mol |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards |
Very flammable. Explosive. |
| Related compounds | |
Related compounds |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references | |
Dicyanoacetylene, also called carbon subnitride or but-2-ynedinitrile (IUPAC), is a compound of carbon and nitrogen with chemical formula C4N2. At room temperature, dicyanoacetylene is a colorless volatile liquid. It has a linear molecular structure, N≡C−C≡C−C≡N (often abbreviated as NC4N), with alternating triple and single covalent bonds. It can be viewed as acetylene with the two hydrogen atoms replaced by cyanide groups.
Because of its high endothermic heat of formation, dicyanoacetylene can explode to carbon powder and nitrogen gas,
- C4N2 → 4 C + N2
and it burns in oxygen with a bright blue-white flame at a temperature of 5,260 K (4,990 °C; 9,010 °F), the hottest flame in oxygen; burned in ozone at high pressure the flame temperature exceeds 6,000 K (5,730 °C; 10,340 °F). Dicyanoacetylene polymerizes at room temperature into a dark solid.