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Identifiers | |
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3D model (
JSmol)
|
|
ChemSpider | |
PubChem
CID
|
|
CompTox Dashboard (
EPA)
|
|
| |
| |
Properties | |
Na2N2O2 | |
Molar mass | 105.99 g/mol |
Appearance | colorless crystals |
Density | 2.466 g/cm3 |
Melting point | 100 °C (212 °F; 373 K) |
Boiling point | 335 °C (635 °F; 608 K) decomposes |
soluble | |
Solubility | insoluble in ethanol |
Except where otherwise noted, data are given for materials in their
standard state (at 25 °C [77 °F], 100 kPa).
|
Sodium hyponitrite is a solid
ionic compound with formula Na
2N
2O
2 or (Na+
)2[ON=NO]2−.
[1]
There are cis and trans forms of the
hyponitrite ion N
2O2−
2. The trans form is more common, but the cis form can be obtained too, and it is more reactive than the trans form.
[1]
[2]
The trans isomer is colorless and soluble in water and insoluble in ethanol and ether. [3] [4]
Sodium hyponitrite (trans) is conventionally prepared by reduction of sodium nitrite with sodium amalgam. [5] [6] [7]
Sodium hyponitrite (trans) was prepared in 1927 by A. W. Scott by reacting alkyl nitrites, hydroxylammonium chloride, and sodium ethoxide [4] [8]
An earlier method, published by D. Mendenhall in 1974, reacted gaseous nitric oxide (NO) with sodium metal in 1,2-dimethoxyethane, toluene, and benzophenone. The salt was then extracted with water. [9] The method was later modified to use pyridine[ citation needed].
Other methods included oxidation of a concentrated solution of hydroxylamine with sodium nitrite in an alkaline medium[ citation needed]; or electrolysis of sodium nitrite. [10]
A variety of
hydrates Na
2N
2O
2(H
2O)x of the trans isomer have been reported, with x including 2, 3.5, 4, 5, 6, 7, 8, and 9;
[11]
[3]
[12] but there is some dispute.
[13]
The hydration water seems to be just trapped in the crystal lattice rather than coordinated to the ions. [13] The anhydrous substance can be obtained by drying the hydrates over phosphorus pentoxide and then heating them to 120 °C. [13]
Sodium hyponitrite (trans) in solution is decomposed by
carbon dioxide CO
2 from air to form
sodium carbonate.
[14]
Liquid
N2O4 oxidises sodium hyponitrite (trans) to give sodium
peroxohyponitrite Na2+
2[ON=NOO]2−).
[15]
[1]
The cis isomer of sodium hyponitrite is a white crystalline solid, insoluble in aprotic solvents, and (unlike the trans isomer) decomposed by water and other protic solvents. [2]
The cis isomer of can be prepared by passing nitric oxide (NO) through a solution of sodium metal in liquid ammonia at −50 °C. [1]
The cis isomer was also obtained in 1996 by
C. Feldmann and
M. Jansen by heating
sodium oxide Na
2O with 77
kPa of
nitrous oxide N
2O (laughing gas) in a sealed tube at 360 °C for 2 hours. The two reagents combined to yield the cis hyponitrite quantitatively as white microcrystals.
[8]
[2]
The anhydrous cis salt is stable up to 325 °C, when it disproportionates to nitrogen and sodium orthonitrite: [2]
It is generally more reactive than the trans isomer. [1]
{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)
![]() | |
Identifiers | |
---|---|
3D model (
JSmol)
|
|
ChemSpider | |
PubChem
CID
|
|
CompTox Dashboard (
EPA)
|
|
| |
| |
Properties | |
Na2N2O2 | |
Molar mass | 105.99 g/mol |
Appearance | colorless crystals |
Density | 2.466 g/cm3 |
Melting point | 100 °C (212 °F; 373 K) |
Boiling point | 335 °C (635 °F; 608 K) decomposes |
soluble | |
Solubility | insoluble in ethanol |
Except where otherwise noted, data are given for materials in their
standard state (at 25 °C [77 °F], 100 kPa).
|
Sodium hyponitrite is a solid
ionic compound with formula Na
2N
2O
2 or (Na+
)2[ON=NO]2−.
[1]
There are cis and trans forms of the
hyponitrite ion N
2O2−
2. The trans form is more common, but the cis form can be obtained too, and it is more reactive than the trans form.
[1]
[2]
The trans isomer is colorless and soluble in water and insoluble in ethanol and ether. [3] [4]
Sodium hyponitrite (trans) is conventionally prepared by reduction of sodium nitrite with sodium amalgam. [5] [6] [7]
Sodium hyponitrite (trans) was prepared in 1927 by A. W. Scott by reacting alkyl nitrites, hydroxylammonium chloride, and sodium ethoxide [4] [8]
An earlier method, published by D. Mendenhall in 1974, reacted gaseous nitric oxide (NO) with sodium metal in 1,2-dimethoxyethane, toluene, and benzophenone. The salt was then extracted with water. [9] The method was later modified to use pyridine[ citation needed].
Other methods included oxidation of a concentrated solution of hydroxylamine with sodium nitrite in an alkaline medium[ citation needed]; or electrolysis of sodium nitrite. [10]
A variety of
hydrates Na
2N
2O
2(H
2O)x of the trans isomer have been reported, with x including 2, 3.5, 4, 5, 6, 7, 8, and 9;
[11]
[3]
[12] but there is some dispute.
[13]
The hydration water seems to be just trapped in the crystal lattice rather than coordinated to the ions. [13] The anhydrous substance can be obtained by drying the hydrates over phosphorus pentoxide and then heating them to 120 °C. [13]
Sodium hyponitrite (trans) in solution is decomposed by
carbon dioxide CO
2 from air to form
sodium carbonate.
[14]
Liquid
N2O4 oxidises sodium hyponitrite (trans) to give sodium
peroxohyponitrite Na2+
2[ON=NOO]2−).
[15]
[1]
The cis isomer of sodium hyponitrite is a white crystalline solid, insoluble in aprotic solvents, and (unlike the trans isomer) decomposed by water and other protic solvents. [2]
The cis isomer of can be prepared by passing nitric oxide (NO) through a solution of sodium metal in liquid ammonia at −50 °C. [1]
The cis isomer was also obtained in 1996 by
C. Feldmann and
M. Jansen by heating
sodium oxide Na
2O with 77
kPa of
nitrous oxide N
2O (laughing gas) in a sealed tube at 360 °C for 2 hours. The two reagents combined to yield the cis hyponitrite quantitatively as white microcrystals.
[8]
[2]
The anhydrous cis salt is stable up to 325 °C, when it disproportionates to nitrogen and sodium orthonitrite: [2]
It is generally more reactive than the trans isomer. [1]
{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)