Sodium nitrate
[CAS 7631-99-4]

Identification

• Classification: Inorganic chemical industry >> Inorganic salt >> Metal nitrates and nitrites
• Name: Sodium nitrate
• Molecular Formula: NaNO₃
• Molecular Weight: 84.99
• CAS Registry Number: 7631-99-4
• EC Number: 231-554-3
• SMILES: [N+](=O)([O-])[O-].[Na+]

Properties

• Density: 2.257 g/mL (Expl.)
• Melting point: 306 °C (Decomposes) (Expl.)
• Boiling point: 380 °C (Decomposes) (Expl.)
• Solubility: water: soluble 900 g/L (20 °C), Slightly soluble in methanol (Expl.)

Safety Data

• Hazard Symbols: GHS03;GHS07 Danger
• Risk Statements: H272-H302-H319
• Safety Statements: P210-P220-P264-P264+P265-P270-P280-P301+P317-P305+P351+P338-P330-P337+P317-P370+P378-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Oxidising solids	Ox. Sol.	3	H272
Acute toxicity	Acute Tox.	4	H302
Oxidising solids	Ox. Sol.	2	H272
Oxidising liquids	Ox. Liq.	1	H271
Oxidising solids	Ox. Sol.	1	H271
Oxidising liquids	Ox. Liq.	2	H272
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Acute toxicity	Acute Tox.	2	H300
Oxidising liquids	Ox. Liq.	3	H272

• Transport Information: UN 1487; UN 1498; UN 1499

chemBlink Chemical Story

Sodium nitrate, CAS 7631-99-4, is the inorganic salt NaNO3, historically known as Chile saltpeter or soda niter. PubChem records a molecular weight of 84.995 and describes it as a white crystalline oxidizing solid. Large natural nitrate deposits in the Atacama Desert made Chilean nitrate an internationally important source of fixed nitrogen before synthetic ammonia transformed the fertilizer industry.

Its nitrate ion supplies nitrogen in a form available to plants, so sodium nitrate has a long history as a fertilizer. Natural nitrate mining became strategically important in the nineteenth and early twentieth centuries because fixed nitrogen was needed not only for agriculture but also for nitric acid and energetic-material manufacture. The Haber-Bosch process greatly reduced dependence on geological nitrate deposits by making ammonia from atmospheric nitrogen.

Sodium nitrate is also an oxidizer. It does not itself burn, but it can accelerate combustion. PubChem and NOAA CAMEO list uses in fertilizers, solid propellants and explosives. Its oxidizing character is therefore both an application and a major handling consideration.

Food chemistry provides another regulated use. The U.S. FDA lists sodium nitrate under specific food regulations with technical functions including antimicrobial action and color-related effects. Such use is controlled by regulation and should not be interpreted as unrestricted addition to foods.

Sodium nitrate thus links natural-resource history with one of chemistry's major technological transitions. Industrial nitrogen fixation changed the supply chain, but NaNO3 remained useful as a fertilizer, oxidizing salt, industrial reagent and regulated food ingredient.

References:
1. PubChem, Sodium nitrate, CID 24268, CAS 7631-99-4.
2. U.S. FDA, Substances Added to Food: Sodium Nitrate.
3. NOAA CAMEO Chemicals, Sodium Nitrate.
4. Smil V. Enriching the Earth. MIT Press, 2001.

Read more stories