Ammonium nitrite
Names
IUPAC name
Ammonium nitrite
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.033.257 Edit this at Wikidata
EC Number
  • 236-598-7
UNII
  • InChI=1S/HNO2.H3N/c2-1-3;/h(H,2,3);1H3 checkY
    Key: CAMXVZOXBADHNJ-UHFFFAOYSA-N checkY
  • InChI=1/HNO2.H3N/c2-1-3;/h(H,2,3);1H3
    Key: CAMXVZOXBADHNJ-UHFFFAOYAU
  • [O-]N=O.[NH4+]
Properties
[NH4]NO2
Molar mass 64.04 g/mol
Appearance colorless or pale yellow crystals
Density 1.69 g/cm3
Melting point Decomposes
118.3 g / 100mL
Explosive data
Shock sensitivity Low
Friction sensitivity Low
Detonation velocity >1000 m/s
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 Explosive
GHS labelling:
GHS01: Explosive GHS07: Exclamation mark
Danger
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 0: Will not burn. E.g. waterInstability 3: Capable of detonation or explosive decomposition but requires a strong initiating source, must be heated under confinement before initiation, reacts explosively with water, or will detonate if severely shocked. E.g. hydrogen peroxideSpecial hazards (white): no code
2
0
3
Flash point Non-flammable
Non-flammable
Related compounds
Other anions
 Ammonium nitrate
Other cations
 Sodium nitrite
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Ammonium nitrite, [NH4]NO2, is the ammonium salt of nitrous acid. It is not used in pure isolated form since it is highly unstable and decomposes into water and nitrogen, even at room temperature.

Preparation

Ammonium nitrite forms naturally in the air and can be prepared by the absorption of equal parts nitrogen dioxide and nitric oxide in aqueous ammonia.[1]

It can also be synthesized by oxidizing ammonia with ozone or hydrogen peroxide, or in a precipitation reaction of barium or lead nitrite with ammonium sulfate, or silver nitrite with ammonium chloride, or ammonium perchlorate with potassium nitrite. The precipitate is filtered off and the solution concentrated. It forms colorless crystals which are soluble in water.

Physical and chemical properties

Ammonium nitrite may explode at a temperature of 60–70 °C,[1] and will decompose quicker when dissolved in a concentrated aqueous solution, than in the form of a dry crystal. Even in room temperature the compound slowly decomposes into water and nitrogen:

[NH4]NO2 → N2 + 2 H2O

It decomposes when heated or in the presence of acid into water and nitrogen.[2] Ammonium nitrite solution is stable at higher pH and lower temperature. If there is any decrease in pH lower than 7.0, it may lead to an explosion, since the nitrite can react to it. A safe pH can be maintained by adding an ammonia solution. The mole ratio of ammonium nitrite to ammonia must be above 10%.

References

  1. ^ a b Thomas Scott; Mary Eagleson (1994). Concise encyclopedia chemistry. Walter de Gruyter. p. 66. ISBN 3-11-011451-8.
  2. ^ "VIAS Encyclopedia: Ammonium Nitrite".


source: http://en.wikipedia.org/wiki/Ammonium_nitrite