Hyponitrous acid
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Names | |||
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Preferred IUPAC name Diazenediol | |||
Systematic IUPAC name N-(Hydroxyimino)hydroxylamine | |||
Other names Hyponitrous acid dimer | |||
Identifiers | |||
CAS Number |
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3D model (JSmol) |
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3DMet |
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ChEBI |
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ChemSpider |
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Gmelin Reference | 141300 | ||
KEGG |
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PubChem CID |
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CompTox Dashboard (EPA) |
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InChI
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Properties | |||
Chemical formula | H2N2O2 | ||
Molar mass | 62.0282 g/mol | ||
Appearance | white crystals | ||
Conjugate base | Hyponitrite | ||
Hazards | |||
Occupational safety and health (OHS/OSH): | |||
Main hazards | explosive when dry | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references |
Hyponitrous acid is a chemical compound with formula H
2N
2O
2 or HON=NOH. It is an isomer of nitramide, H2N−NO2; and a formal dimer of azanone, HNO.
Hyponitrous acid forms two series of salts, the hyponitrites containing the [ON=NO]2− anion, and the "acid hyponitrites" containing the [HON=NO]− anion.[1]
Structure and properties
There are two possible structures of hyponitrous acid, trans and cis. trans-Hyponitrous acid forms white crystals that are explosive when dry. In aqueous solution, it is a weak acid (pKa1 = 7.21, pKa2 = 11.54),[2] and decomposes to nitrous oxide and water with a half life of 16 days at 25 °C at pH 1–3:
Since this reaction is not reversible, N
2O should not be considered as the anhydride of H
2N
2O
2.[1]
The cis acid is not known,[1] but its sodium salt can be obtained.[3]
Preparation
Hyponitrous acid (trans) can be prepared from silver(I) hyponitrite and anhydrous HCl in ether:
Spectroscopic data indicate a trans configuration for the resulting acid.[3]
It can also be synthesized from hydroxylamine and nitrous acid:
Biological aspects
In enzymology, a hyponitrite reductase is an enzyme that catalyzes the chemical reaction[4]
References
- ^ a b c Wiberg, Egon; Holleman, Arnold Frederick (2001). Inorganic Chemistry. Elsevier. ISBN 0-12-352651-5.
- ^ Perrin, D. D., ed. (1982) [1969]. Ionisation Constants of Inorganic Acids and Bases in Aqueous Solution. IUPAC Chemical Data (2nd ed.). Oxford: Pergamon (published 1984). Entry 120. ISBN 0-08-029214-3. LCCN 82-16524.
- ^ a b Catherine E. Housecroft; Alan G. Sharpe (2008). "Chapter 15: The group 15 elements". Inorganic Chemistry (3rd ed.). Pearson. p. 468. ISBN 978-0-13-175553-6.
- ^ "ENZYME - 1.7.1.5 Hyponitrite reductase".
- v
- t
- e
- H3AsO3
- H3AsO4
- HArF
- HAt
- HSO3F
- H[BF4]
- HBr
- HBrO
- HBrO2
- HBrO3
- HBrO4
- HCl
- HClO
- HClO2
- HClO3
- HClO4
- HCN
- HCNO
- H2CrO4/H2Cr2O7
- H2CO3
- H2CS3
- HF
- HFO
- HI
- HIO
- HIO2
- HIO3
- HIO4
- HMnO4
- H2MnO4
- H2MoO4
- HNC
- NaHCO3
- HNCO
- HNO
- HNO2
- HNO3
- H2N2O2
- HNO5S
- H3NSO3
- H2O
- H2O2
- H2O3
- H2O4
- H2O5
- H3PO2
- H3PO3
- H3PO4
- H4P2O7
- H5P3O10
- H2[PtCl6]
- H2S
- H2S2
- H2Se
- H2SeO3
- H2SeO4
- H4SiO4
- H2[SiF6]
- HSCN
- HNCS
- H2SO3
- H2SO4
- H2SO5
- H2S2O3
- H3O
- H2S2O6
- H2S2O7
- H2S2O8
- CF3SO3H
- H2Te
- H2TeO3
- H6TeO6
- H4TiO4
- H2Po
- H[Co(CO)4]