Potassium nitrate
General
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|---|---|
| Name | Potassium nitrate |
| Chemical formula | KNO3 |
| Appearance | White or dirty gray solid |
Physical
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| 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
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| 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
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| 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 |
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SI units were used where possible. Unless otherwise stated, standard conditions were used.
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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.
