Dinitrogen trioxide
{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 443695072
| Name = Dinitrogen trioxide
| ImageFile = Dinitrogen trioxide resonance hybrid.png
| ImageClass = skin-invert-image
| ImageName = Dinitrogen trioxide resonance hybrid
| ImageFile1 = Beautiful nitrogen trioxide2.jpg
| ImageName1 = Dinitrogen trioxide is blue
| IUPACName = N-Oxonitramide{{Cite web|url=https://pubchem.ncbi.nlm.nih.gov/compound/nitrogen%20trioxide#section=IUPAC-Name&fullscreen=true|title = Dinitrogen trioxide}}
| OtherNames = {{ubl|Nitrous anhydride|Nitrogen sesquioxide}}
| Section1 = {{Chembox Identifiers
| CASNo_Ref = {{cascite|correct|??}}
| CASNo = 10544-73-7
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 55446
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 29799
| EINECS = 234-128-5
| PubChem = 61526
| UNNumber = 2421
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 16E0524PXI
| InChI = 1/N2O3/c3-1-2(4)5
| InChIKey = LZDSILRDTDCIQT-UHFFFAOYAC
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/N2O3/c3-1-2(4)5
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = LZDSILRDTDCIQT-UHFFFAOYSA-N
| SMILES = [O-][N+](=O)N=O
}}
| Section2 = {{Chembox Properties
| N=2|O=3
| Appearance = Deep blue liquid
| Density = {{ubl|1.447 g/cm3, liquid|1.783 g/cm3, gas}}
| BoilingPtC = 3.5
| BoilingPt_notes = (dissociates)
| Solubility = reacts to form nitrous acid
| SolubleOther = soluble in ether
| MagSus = −16.0·10−6 cm3/mol
}}
| Section3 = {{Chembox Structure
| MolShape = planar, Cs
| Dipole = 2.122 D
}}
| Section4 = {{Chembox Thermochemistry
| DeltaHf = 91.20 kJ/mol
| Entropy = 314.63 J/(mol·K)
| HeatCapacity = 65.3 J/(mol·K)
}}
| Section7 = {{Chembox Hazards
| ExternalSDS =
| GHSPictograms = {{GHS03}}{{GHS05}}{{GHS06}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|H270|H310+H330|H314}}
| PPhrases = {{P-phrases|220|244|260|262|264|270|271|280|284|301+330+331|302+350|303+361+353|304+340|305+351+338|310|320|321|322|361|363|370+376|403|403+233|405|410+403|501}}
| MainHazards =
| NFPA-H = 4
| NFPA-F = 0
| NFPA-R = 2
| NFPA-S = OX
| FlashPt = Non-flammable
}}
| Section9 = {{Chembox Related
| OtherCompounds = {{ubl|Nitrogen oxide|Nitrous acid|Nitrous oxide|Nitric oxide|Nitrogen dioxide|Dinitrogen tetroxide|Dinitrogen pentoxide|Nitrogen trioxide}}
}}
}}
Dinitrogen trioxide (also known as nitrous anhydride) is the inorganic compound with the formula {{chem2|N2O3|auto=1}}. 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):{{Greenwood&Earnshaw1st|pages=521–22}}
:{{chem|•|NO}} + {{chem|•|NO|2}} {{Eqm}} {{chem|N|2|O|3}}
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.{{Greenwood&Earnshaw2nd|page=444}} At higher temperatures the equilibrium favors the constituent gases, with KD = 193 kPa (25°C).{{Holleman&Wiberg}}{{cln|reason=The unit of mrasurement of a dissociatio n constant is not kPa! And you failed to tell to the readers what is the vslue of the |date=June 2023}}
This compound is sometimes called "nitrogen trioxide", but this name properly refers to another compound, the (uncharged) nitrate radical {{chem2|•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 {{chem2|O\dN\sNO2}}, which can be described as a nitroso group {{chem2|\sN\dO}} attached to a nitro group {{chem2|\sNO2}} by a single bond between the two nitrogen atoms. This isomer is considered as the "anhydride" of the unstable nitrous acid ({{chem2|HNO2}}), and produces it when mixed with water, although an alternative structure might be anticipated for the true anhydride of nitrous acid (i.e., {{chem2|O\dN\sO\sN\dO}}). This isomer can be produced from the reaction of tetrabutylammonium nitrite and triflic anhydride in dichloromethane solution at −30°C.{{cite journal | last=Reddy | first=G. Sudhakar | last2=Suh | first2=Elijah J. | last3=Corey | first3=E. J. | title=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 | journal=Organic Letters | volume=24 | issue=23 | date=2022-06-17 | issn=1523-7052 | pmid=35653176 | doi=10.1021/acs.orglett.2c01466 | pages=4202–4206}}
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 {{chem2|N2O3}} to water solutions of bases:
:{{chem2|N2O3 + 2 NaOH → 2 NaNO2 + H2O}}
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 {{chem2|N2O3}} molecule is planar and exhibits Cs symmetry. The dimensions displayed on the picture below come from microwave spectroscopy of low-temperature, gaseous {{chem2|N2O3}}:
{{center|
File:Dinitrogen-trioxide-2D-geometry.png
}}Similar to nitronium nitrate, this molecule can also co-exist in equilibrium with an ionic gas called nitrosonium nitrite ([NO]+[NO2]–) {{Cite journal |last=Zakharov |first=I. I. |last2=Zakharova |first2=O. I. |date=2009-04-01 |title=Nitrosonium nitrite isomer of N2O3: Quantum-chemical data |url=https://doi.org/10.1007/s10947-009-0031-1 |journal=Journal of Structural Chemistry |language=en |volume=50 |issue=2 |pages=212–218 |doi=10.1007/s10947-009-0031-1 |issn=1573-8779}}
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References
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External links
- [https://web.archive.org/web/20040205090004/http://www.npi.gov.au/database/substance-info/profiles/67.html National Pollutant Inventory – Oxides of nitrogen fact sheet]
- [http://www.webelements.com/webelements/compounds/text/N/N2O3-10544737.html Webelements: Compound data – dinitrogen trioxide]
- [http://www.c-f-c.com/supportdocs/nitrogen_oxi.htm Oxides of nitrogen – synthesis and uses] {{Webarchive|url=https://web.archive.org/web/20190731015132/http://www.c-f-c.com/supportdocs/nitrogen_oxi.htm |date=2019-07-31 }}
- [http://www.chem.msu.su/rus/handbook/ivtan/79.html Ivtantermo – thermodynamic properties of dinitrogen trioxide at a wide range of elevated temperatures]
{{nitrogen compounds}}
{{oxygen compounds}}
{{Oxides}}