| IUPAC name
| Preferred IUPAC name
| Other names
|Molar mass||76.01 g/mol|
|Appearance||Deep blue gas|
|Density|| 1.447 g/cm3 (liquid)|
1.783 g/cm3 (gas)
|Melting point||−100.7 °C (−149.3 °F; 172.5 K)|
|Boiling point||3.5 °C (38.3 °F; 276.6 K) (dissociates)|
|Solubility|| Reacts with alcohols|
Soluble in CCl4, chloroform, diethyl ether, sulfuryl chloride, liq. xenon
Std enthalpy of
|Safety data sheet||None|
| Nitrous oxide|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Dinitrogen trioxide is a chemical compound with the chemical formula N2O3.
It is the anhydride of the unstable nitrous acid (HNO2) and produces it when mixed into water.
- N2O3 + 2 H2O → 2 HNO2
If the nitrous acid is not then used up quickly, it decomposes into nitric oxide and nitric acid. Nitrite salts are sometimes produced by adding N2O3 to alkaline solutions:
- N2O3 + 2 NaOH → 2 NaNO2 + H2O
Dinitrogen trioxide is a blue gas, with a strong odor.
This compound is not sold and has to be made in situ.
- NO + NO2 ⇌ N2O3
Dinitrogen trioxide is only isolable at low temperatures, i.e. in the liquid and solid phases. At higher temperatures the equilibrium favors the constituent gases, with Kdiss = 193 kPa (25 °C).
- Make nitrites
Dinitrogen trioxide is toxic and corrosive.
Can only be kept at very low temperatures, but not for long.
Can be neutralized by bubbling it in alkaline water.