[7] KCl is used as a fertilizer,[8] in medicine, in scientific applications, domestic water softeners (as a substitute for sodium chloride salt), and in food processing, where it may be known as E number additive E508.

Potassium plays a vital role in various plant physiological processes, including enzyme activation, photosynthesis, protein synthesis, and water regulation.

[24] It is also an ingredient in Oral Rehydration Therapy (ORT)/solution (ORS) to reduce hypokalemia caused by diarrhoea.

[32] [33] [34] In the United States, potassium chloride is used as the final drug in the three-injection sequence of lethal injection as a form of capital punishment.

It is also used in medicine, lethal injections, scientific applications, food processing, soaps, and as a sodium-free substitute for table salt for people concerned about the health effects of sodium.

[citation needed] It is sometimes used in solution as a completion fluid in petroleum and natural gas operations, as well as being an alternative to sodium chloride in household water softener units.

[citation needed] Glass manufacturers use granular potash as a flux, lowering the temperature at which a mixture melts.

Because potash imparts excellent clarity to glass, it is commonly used in eyeglasses, glassware, televisions, and computer monitors.

It also emits a relatively low level of 511 keV gamma rays from positron annihilation, which can be used to calibrate medical scanners.

This agent fell out of favor with the introduction of potassium bicarbonate (Purple-K) dry chemical in the late 1960s, which was much less corrosive, as well as more effective.

[citation needed] Potassium chloride is also an optical crystal with a wide transmission range from 210 nm to 20 μm.

[citation needed] The typical amounts of potassium chloride found in the diet appear to be generally safe.

The LD50 of orally ingested potassium chloride is approximately 2.5 g/kg, or 190 grams (6.7 oz) for a body mass of 75 kilograms (165 lb).

It adopts a face-centered cubic structure known as the B1 phase with a lattice constant of roughly 6.3 Å. Crystals cleave easily in three directions.

It is also extracted from salt water and can be manufactured by crystallization from solution, flotation or electrostatic separation from suitable minerals.