Английская Википедия:Dinitrogen trioxide

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Шаблон:Chembox Dinitrogen trioxide (also known as nitrous anhydride) is the inorganic compound with the formula Шаблон:Chem2. It is a nitrogen oxide. It forms upon mixing equal parts of nitric oxide and nitrogen dioxide and cooling the mixture below −21 °C (−6 °F):[1]

Шаблон:Chem2

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).[3]Шаблон:Cln

This compound is sometimes called "nitrogen trioxide", but this name properly refers to another compound, the (uncharged) nitrate radical Шаблон:Chem2.

Structure and bonding

Dinitrogen trioxide molecule contains an N–N bond. One of the numerous resonant structures of the molecule of dinitrogen trioxide is Шаблон:Chem2, which can be described as a nitroso group Шаблон:Chem2 attached to a nitro group Шаблон:Chem2 by a single bond between the two nitrogen atoms. This isomer is considered as the "anhydride" of the unstable nitrous acid (Шаблон:Chem2), and produces it when mixed with water, although an alternative structure might be anticipated for the true anhydride of nitrous acid, i.e. Шаблон:Chem2. This isomer can be produced from the reaction of tetrabutylammonium nitrite and triflic anhydride in dichloromethane solution at -30°C.[4]

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 Шаблон:Chem2 to water solutions of bases:

Шаблон:Chem2

Typically, N–N bonds are similar in length to that in hydrazine (145 pm). Dinitrogen trioxide, however, has an unusually long N–N bond at 186 pm. Some other nitrogen oxides also possess long N–N bonds, including dinitrogen tetroxide (175 pm). The Шаблон:Chem2 molecule is planar and exhibits Cs symmetry. The dimensions displayed on the picture below come from microwave spectroscopy of low-temperature, gaseous Шаблон:Chem2:[1] Шаблон:Center

References

Шаблон:Reflist

External links

Шаблон:Nitrogen compounds Шаблон:Oxygen compounds Шаблон:Oxides