Sodium nitrite

Sodium nitrite

Identifiers
CAS Number	7632-00-0 Y
3D model (Jmol)	Interactive image
ChEBI	CHEBI:78870 N
ChEMBL	ChEMBL93268 Y
ChemSpider	22689 Y
ECHA InfoCard	100.028.687
EC Number	231-555-9
E number	E250 (preservatives)
PubChem	24269
RTECS number	RA1225000
UNII	M0KG633D4F Y
UN number	1500
InChI InChI=1S/HNO2.Na/c2-1-3;/h(H,2,3);/q;+1/p-1 Y Key: LPXPTNMVRIOKMN-UHFFFAOYSA-M Y InChI=1/HNO2.Na/c2-1-3;/h(H,2,3);/q;+1/p-1 Key: LPXPTNMVRIOKMN-REWHXWOFAO
SMILES N(=O)[O-].[Na+]
Properties
Chemical formula	NaNO2
Molar mass	68.9953 g/mol
Appearance	white or slightly yellowish solid
Density	2.168 g/cm3
Melting point	271 °C (520 °F; 544 K) (decomposes at 320 °C)
Solubility in water	71.4 g/100 mL (0 °C) 84.8 g/100 mL (25 °C) 160 g/100 mL (100 °C)
Solubility	soluble in methanol (4.4 g/100 mL) ethanol slightly soluble in diethyl ether (0.3 g/100 mL) very soluble in ammonia
Acidity (pKa)	~9
Magnetic susceptibility (χ)	−14.5·10−6 cm3/mol
Refractive index (nD)	1.65
Structure
Crystal structure	Trigonal
Thermochemistry
Std molar entropy (So298)	106 J/mol K
Std enthalpy of formation (ΔfHo298)	−359 kJ/mol
Gibbs free energy (ΔfG˚)	−295 kJ/mol
Pharmacology
ATC code	V03AB08 (WHO)
Hazards
Safety data sheet	External MSDS
EU classification (DSD)	O T N
R-phrases	R8, R25, R50
S-phrases	(S1/2), S45, S61
NFPA 704	0 3 1 OX
Autoignition temperature	489 °C (912 °F; 762 K)
Lethal dose or concentration (LD, LC):
LD50 (median dose)	180 mg/kg (rats, oral)
Related compounds
Other anions	Sodium nitrate
Other cations	Potassium nitrite Ammonium nitrite Lithium nitrite
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Sodium nitrite is the inorganic compound with the chemical formula NaNO₂. It is a white to slightly yellowish crystalline powder that is very soluble in water and is hygroscopic. It is a useful precursor to a variety of organic compounds, such as pharmaceuticals, dyes, and pesticides, but it is probably best known as a food additive to prevent botulism.

It is on the World Health Organization's List of Essential Medicines, the most important medications needed in a basic health system.

The main use of sodium nitrite is for the industrial production of organonitrogen compounds. It is a reagent for conversion of amines into diazo compounds, which are key precursors to many dyes, such as diazo dyes. Nitroso compounds are produced from nitrites. These are used in the rubber industry.

Other applications include uses in photography. It may also be used as an electrolyte in electrochemical grinding manufacturing processes, typically diluted to about 10% concentration in water. It is used in a variety of metallurgical applications, for phosphatizing and detinning.

Sodium nitrite is an effective corrosion inhibitor and is used as an additive in industrial greases, as an aqueous solution in closed loop cooling systems, and in a molten state as a heat transfer medium.

Sodium nitrite is used together with sodium thiosulfate to treat cyanide poisoning.

It is in the section "antidotes and other substances used in poisonings" of the World Health Organization's List of Essential Medicines, the most important medications needed in a basic health system.