|White or dirty gray solid|
|38 g in 100g water|
|Ingestion||May cause GI irritation, nausea, vomiting, diarrhea.|
|Inhalation||Irritation, long term exposure may be fatal.|
|SI units were used where possible. Unless otherwise stated, standard conditions were used.|
Its common names include saltpetre (from 14th century medieval latin sal petrae: "stone salt"), American English saltpeter, Chilean saltpetre, and nitre. The name "saltpeter" is also applied to sodium nitrate.
It is the oxidising (oxygen-supplying) 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 cave walls or the drainings of decomposing organic material.
One of the most useful applications of potassium nitrate is in the production of of nitric acid, by adding concentrated sulphuric acid to an aqueous solution of potassium nitrate, yielding nitric acid and potassium chloride which are separated through fractional distillation.
Potassium nitrate is also used as a fertiliser, as a model rocket propellant, and for certain pyrotechnic combinations, such as the renowned sugar-saltpetre mix which gives rise to a lot of smoke.
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.