Sodium nitrite

Sodium nitrite
	Unit cell of sodium nitrite under standard conditions
Names
	IUPAC name Sodium nitrite
	Preferred IUPAC name Sodium nitrite
Identifiers
CAS Number	7632-00-0 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:78870 ;
ChEMBL	ChEMBL93268 ;
ChemSpider	22689 ;
ECHA InfoCard	100.028.687
EC Number	231-555-9;
E number	E250 (preservatives)
KEGG	D05865;
PubChem CID	23668193;
RTECS number	RA1225000;
UNII	M0KG633D4F ;
UN number	1500 3287
CompTox Dashboard (EPA)	DTXSID0020941 ;
	InChI InChI=1S/HNO2.Na/c2-1-3;/h(H,2,3);/q;+1/p-1 Key: LPXPTNMVRIOKMN-UHFFFAOYSA-M ; 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 crystalline 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 in methanol	4.4 g/(100 mL)
Solubility in ethanol	Soluble
Solubility in diethyl ether	0.3 g/(100 mL)
Solubility in ammonia	Very soluble
Acidity (pKa)	~9
Magnetic susceptibility (χ)	−14.5·10−6 cm3/mol
Refractive index (nD)	1.65
Structure
Crystal structure	Orthorhombic
Space group	Im2m
Lattice constant	a = 3.5653(8) Å, b = 5.5728(7) Å, c = 5.3846(13) Å
Formula units (Z)	2
Thermochemistry
Std molar; entropy (S⦵298)	106 J/(mol·K)
Std enthalpy of; formation (ΔfH⦵298)	−359 kJ/mol
Gibbs free energy (ΔfG⦵)	−295 kJ/mol
Pharmacology
ATC code	V03AB08 (WHO)
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H272, H301, H319, H400
Precautionary statements	P220, P273, P301+P310, P305+P351+P338
NFPA 704 (fire diamond)	3 0 1 OX
Autoignition; temperature	489 °C (912 °F; 762 K)
	Lethal dose or concentration (LD, LC):
LD50 (median dose)	180 mg/kg (rats, oral)
Safety data sheet (SDS)	"Sodium nitrite". Safety Data Sheet. Sigma-Aldrich. 28 December 2022.
Related compounds
Other anions	Sodium nitrate
Other cations	Potassium nitrite; Ammonium nitrite; Lithium nitrite; Silver nitrite;
Related compounds	Nitrous acid
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Sodium nitrite is an inorganic compound with the chemical formula Na N O₂. It is a white to slightly yellowish crystalline powder that is very soluble in water and is hygroscopic. From an industrial perspective, it is the most important nitrite salt. It is a precursor to a variety of organic compounds, such as pharmaceuticals, dyes, and pesticides, but it is probably best known as a food additive used in processed meats and (in some countries) in fish products.