Substance profile
Potassium nitrite
Potassium nitrite is white or slightly yellow granules or rods.
01 · Identification
What Potassium nitrite is
Potassium nitrite is white or slightly yellow granules or rods. Its molecular formula is KNO2 and its molecular weight is 85.104 g/mol. It boils at 537 °C, melts at 441 °C.
Under the GHS it carries the signal word Danger.
02 · GHS classification
Hazards and label elements
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
| Code | Hazard statement |
|---|---|
| H272 | May intensify fire; oxidiser. |
| H301 | Toxic if swallowed. |
| H400 | Very toxic to aquatic life. |
Precautionary statements: P270, P273, P301, P310, P330, P391, P501
03 · Physical and chemical properties
Potassium nitrite properties
Every value is shown with the conditions it was measured under and the source it came from. Where sources disagree, all values are listed rather than one being picked — the difference is usually a different form of the substance, not an error.
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 537 °C (998.6 °F) | explodes | HSDB |
| Melting point | 441 °C (825.8 °F) | HSDB | |
| 440 °C (824 °F) | DOE PAC | ||
| Density | 1.915 g/cm³ | HSDB | |
| 1.9 g/cm³ | ICSC | ||
| 1.915 g/cm³ | at 25 °C | DOE PAC | |
| Solubility | SOL IN HOT ALCOHOL; VERY SOL IN LIQUID AMMONIA | HSDB | |
| 306 parts by wt per 100 parts by wt of water at 20 °C | at 20 °C | HSDB | |
| 312 g/100g of water at 25 °C | at 25 °C | HSDB | |
| Lower explosive limit (LEL) | Prolonged exposure to fire or heat may result in an explosion. | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
04 · Fire and explosion
Fire and explosion behaviour of Potassium nitrite
These are descriptions rather than measured values, so they are kept out of the table above and quoted here with the source that reported them.
Fire and explosion
May explode on heating above 530 °C ... /Potassium nitrite/ is a strong oxidant and reacts with combustible and reducing materials causing fire and explosion hazard.
Source: HSDB
05 · Handling and storage
Storing and handling Potassium nitrite
Storage conditions
Keep well closed.
Source: Hazardous Substances Data Bank (HSDB)
Incompatible materials
Addition of ammonium sulfate to the fused /potassium/ nitrite causes effervescence and ignition.
Source: Hazardous Substances Data Bank (HSDB)
Reactivity
POTASSIUM NITRITE is an oxidizing agent. Mixtures with phosphorus, tin(II) chloride or other reducing agents may react explosively [Bretherick 1979 p. 108-109]. Contamination by ammonium compounds can initiate spontaneous decomposition. The resulting heat may ignite surrounding combustible material. Reacts with acids to form toxic nitrogen dioxide gas. Mixing with liquid ammonia forms dipotassium nitrite, which is very reactive and easily explosive [Mellor 2, Supp. 3:1566 1963]. Melting together with an ammonium salt leads to a violent explosion [Von Schwartz 1918 p. 299]. A mixture with potassium cyanide may cause an explosion. When a little ammonium sulfate is added to fused potassium nitrite, a vigorous reaction occurs attended by flame [Mellor 2:702. 1946-47].
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Potassium nitrite in the storage compatibility matrix →