Saltpetre

Properties

General
Name	Potassium nitrate
Chemical formula	KNO3
Appearance	White or dirty gray solid
Physical
Formula weight	101.1 amu
Melting point	607 K (334 °C)
Boiling point	decomposes at 673 K (400 °C)
Density	2.1 ×103 kg/m3
Crystal structure	Aragonite
Solubility	38 g in 100g water
Thermochemistry
ΔfH0gas	? kJ/mol
ΔfH0liquid	-483 kJ/mol
ΔfH0solid	-495 kJ/mol
S0gas, 1 bar	? J/mol·K
S0liquid, 1 bar	? J/mol·K
S0solid	? J/mol·K
Safety
Ingestion	May cause GI irritation, nausea, vomiting, diarrhea.
Inhalation	Irritation, long term exposure may be fatal.
Skin	Low hazard.
Eyes	Low hazard.
More info	Hazardous Chemical Database
SI units were used where possible. Unless otherwise stated, standard conditions were used. Disclaimer and references

The chemical compound potassium nitrate is a naturally occurring mineral source of nitrogen. It is a nitrate with chemical formula KNO₃. Its common names include saltpetre (American English saltpeter), Chilean saltpetre, and nitre. The name "saltpeter" is also applied to sodium nitrate.

It is the oxidising component of gunpowder. Prior to the large-scale industrial fixation of nitrogen (the Haber process), a major source of saltpetre was the deposits crystallising from the drainings of dung-heaps; thereby making dung-heaps a valuable military resource.

An urban legend holds that soldiers, sailors, and other young men in institutional situations are secretly administered saltpetre in their food, especially during bootcamp, to suppress their sexual urges. It is conjectured that the troops were employing a folk etymology and replacing "salt" with "soft". The reduction in sexual urges does in fact occur, but is caused by physical exhaustion related to intense training.

Related Material

• Nitric acid

Referenced By