Dinitrogen trioxide is only isolable at low temperatures (i.e., in the liquid and solid phases). In liquid and solid states, it has a deep blue color.[2] At higher temperatures the equilibrium favors the constituent gases, with KD = 193 kPa (25 °C).[5][clarification needed]
This compound is sometimes called "nitrogen trioxide", but this name properly refers to another compound, the (uncharged) nitrate radical•NO3.
Structure and bonding
Dinitrogen trioxide molecule contains an N–N bond. One of the numerous resonant structures of the molecule of dinitrogen trioxide is O=N−NO2, which can be described as a nitroso group−N=O attached to a nitro group−NO2 by a single bond between the two nitrogen atoms. This isomer is considered as the "anhydride" of the unstable nitrous acid (HNO2), and produces it when mixed with water, although an alternative structure might be anticipated for the true anhydride of nitrous acid (i.e., O=N−O−N=O). This isomer can be produced from the reaction of tetrabutylammonium nitrite and triflic anhydride in dichloromethane solution at -30°C.[6]
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 water solutions of bases:
^Holleman, Arnold Frederik; Wiberg, Egon (2001), Wiberg, Nils (ed.), Inorganic Chemistry, translated by Eagleson, Mary; Brewer, William, San Diego/Berlin: Academic Press/De Gruyter, ISBN0-12-352651-5
^Reddy, G. Sudhakar; Suh, Elijah J.; Corey, E. J. (2022-06-17). "Nitrosyl Triflate and Nitrous Anhydride, Same Mode of Generation, but Very Different Reaction Pathways. Direct Synthesis of 1,2-Oxazetes, Nitroso or Bisoxazo Compounds from Olefins". Organic Letters. 24 (23): 4202–4206. doi:10.1021/acs.orglett.2c01466. ISSN1523-7052. PMID35653176.
