Dinitrogen dioxide is an inorganic compound having molecular formula . Many structural isomers are possible. The covalent bonding pattern O=NâÂÂN=O (a non-cyclic dimer of nitric oxide (NO)) is predicted to be the most stable isomer based on ab initio calculations and is the only one that has been experimentally produced. In the solid form, the molecules have C<sub>2v</sub> symmetry: the entire structure is planar, with the two oxygen atoms cis across the NâÂÂN bond. The OâÂÂN distance is 1.15 à, the NâÂÂN distance is 2.33 à, and the O=NâÂÂN angle is 95ð.
It is an intermediate in the high-pressure disproportionation of nitric oxide: