Potassium Nitrate

potassium nitrate (KNO₃), also called saltpetre or nitre, an ionic white crystalline salt made up of potassium ions and nitrate ions. Uses of potassium nitrate include the manufacture of fertilizers, pesticides, glass, fireworks, explosives, and rocket fuels. It is also used as a food preservative, and when added to meat it causes a reaction between the myoglobin and hemoglobin in the blood, making the meat appear red in colour. It is also used as an additive in some toothpastes to help with tooth sensitivity. Potassium nitrate is toxic to humans in high levels, so its use is carefully controlled when human consumption is involved.

salt flat with potassium nitrate deposits

It is found in impure form, often called saltpetre (also called nitre), its name derived from the Latin words sal patrae, meaning “salt of the rock,” as it is often found as a white material deposited on the surface of rocks. Saltpetre can form on the surface of soil in various warm-climate locations, including in Egypt, Spain, and Iran. In such places, feces, urine, and decaying plants react with moisture and an alkaline soil to create nitrates. These nitrates dissolve in rainwater, and white deposits of potassium nitrate are left behind when this water evaporates. Many caves throughout the world have large deposits of saltpetre due to large amounts of bat guano and urine found there.