Potassium chloride (KCl) is a metal halide salt composed of potassium and chlorine. It is odorless and has a white or colorless vitreous crystal appearance. The solid dissolves readily in water and its solutions have a salt-like taste. KCl is used as a fertilizer, in medicine, in scientific applications, and in food processing, where it may be known as E number additive E508.
In a few states of the United States it is used to cause cardiac arrest as the third drug in the "three drug cocktail" for executions by lethal injection. It occurs naturally as the mineral sylvite, and in combination with sodium chloride as sylvinite.
Muriate of potash
3D model (JSmol)
|E number||E508 (acidity regulators, ...)|
|Molar mass||74.5513 g·mol−1|
|Appearance||white crystalline solid|
|Melting point||770 °C (1,420 °F; 1,040 K)|
|Boiling point||1,420 °C (2,590 °F; 1,690 K)|
|217.1 g/L (0 °C) |
253.9 g/L (20 °C)
360.5 g/L (100 °C)
|Solubility||Soluble in glycerol, alkalies |
Slightly soluble in alcohol Insoluble in ether
Refractive index (nD)
|1.4902 (589 nm)|
|face centered cubic|
|Fm3m, No. 225|
a = 629.2 pm
Std enthalpy of
|A12BA01 (WHO) B05XA01 (WHO)|
|Oral, IV, IM|
|Renal: 90%; Fecal: 10%|
|Safety data sheet||ICSC 1450|
|Lethal dose or concentration (LD, LC):|
LD50 (median dose)
|2600 mg/kg (oral, rat)|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
The majority of the potassium chloride produced is used for making fertilizer, called potash, since the growth of many plants is limited by potassium availability. The two main types of potash are: Muriate of Potash (MOP, Potassium Chloride) and Sulphate of Potash (SOP, Potassium Sulphate). While SOP typically sells at a premium to MOP, the vast majority of potash fertilizer worldwide is sold as MOP.
Potassium is vital in the human body, and potassium chloride by mouth is the common means to treat low blood potassium, although it can also be given intravenously. The intravenous form is on the World Health Organization's List of Essential Medicines, the most important medications needed in a basic health system.
It can be used as a salt substitute for food, but due to its weak, bitter, unsalty flavor, it is often mixed with ordinary table salt (sodium chloride) improve the taste to form low sodium salt. The addition of 1 ppm of thaumatin considerably reduces this bitterness. Complaints of bitterness or a chemical or metallic taste are also reported with potassium chloride used in food.
As a chemical feedstock, it is used for the manufacture of potassium hydroxide and potassium metal. 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.
It is used as a supplement in animal feed to boost the amount of nutrients in the feed, which in turn promotes healthy growth in animals. As an added benefit, it is known to increase milk production.
Glass manufacturers use granular potash as a flux, lowering the temperature at which a mixture melts. Because potash confers excellent clarity to glass, it is commonly used in eyeglasses, glassware, televisions and computer monitors.
KCl is useful as a beta radiation source for calibration of radiation monitoring equipment, because natural potassium contains 0.0118% of the isotope 40K. One kilogram of KCl yields 16350 becquerels of radiation consisting of 89.28% beta and 10.72% gamma with 1.46083 MeV.
Potassium chloride is used in some de-icing products that are designed to be safer for pets and plants, though these are inferior in melting quality to calcium chloride [lowest usable temperature 12 °F (−11 °C) v. −25 °F (−32 °C)]. It is also used in various brands of bottled water, as well as in bulk quantities for fossil fuel drilling purposes.
Potassium chloride was once used as a fire extinguishing agent, used in portable and wheeled fire extinguishers. Known as Super-K dry chemical, it was more effective than sodium bicarbonate-based dry chemicals and was compatible with protein foam. 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 and more effective. It is rated for B and C fires.
Potassium chloride is also an optical crystal with a wide transmission range from 210 nm to 20 µm. While cheap, KCl crystal is hygroscopic. This limits its application to protected environments or short-term uses such as prototyping. Exposed to free air, KCl optics will "rot". Whereas KCl components were formerly used for infrared optics, it has been entirely replaced by much tougher crystals such as zinc selenide.
Potassium chloride has also been used to produce heat packs which employ exothermic chemical reactions, but these have mostly been discontinued with the advent of cheaper and more efficient methods, such as the oxidation of metals ('Hot Hands' one-time-use products) or the crystallization of sodium acetate (multiple-use products).
The typical amounts of potassium chloride found in the diet appear to be generally safe. In larger quantities, however, potassium chloride is toxic. 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). In comparison, the LD50 of sodium chloride (table salt) is 3.75 g/kg.
Intravenously, the LD50 of potassium chloride is far smaller, at about 57.2 mg/kg to 66.7 mg/kg; this is found by dividing the lethal concentration of positive potassium ions (about 30 to 35 mg/kg) by the proportion by mass of potassium ions in potassium chloride (about .52445 mg K+/mg KCl). In such quantities, it has severe consequences on the cardiac muscles, potentially causing cardiac arrest and rapid death. For this reason, it is used as the third and final drug delivered in the lethal injection process.
KCl is soluble in a variety of polar solvents.
(g/kg of solvent at 25 °C)
|Liquid sulfur dioxide||0.41|
Solutions of KCl are common standards, for example for calibration of the electrical conductivity of (ionic) solutions, since KCl solutions are stable, allowing for reproducible measurements. In aqueous solution, it is essentially fully ionized into solvated K+ and Cl– ions.
Although potassium is more electropositive than sodium, KCl can be reduced to the metal by reaction with metallic sodium at 850 °C because the more volatile potassium can be removed by distillation (see Le Chatelier's principle):
The crystal structure of potassium chloride is like that of NaCl. It adopts a face-centered cubic structure. Its lattice constant is roughly 6.3 Å. Crystals cleave easily in three directions.
Some other properties are
As with other compounds containing potassium, KCl in powdered form gives a lilac flame.
Potassium chloride is extracted from minerals sylvite, carnallite, and potash. It is also extracted from salt water and can be manufactured by crystallization from solution, flotation or electrostatic separation from suitable minerals. It is a by-product of the production of nitric acid from potassium nitrate and hydrochloric acid.
The vast majority of potassium chloride is produced as agricultural and industrial grade potash in Saskatchewan, Canada, as well as Russia and Belarus. Saskatchewan alone accounted for over 25% of the world's potash production in 2017.
Potassium chloride is inexpensively available and is rarely prepared intentionally in the laboratory. It can be generated by treating potassium hydroxide (or other potassium bases) with hydrochloric acid:
This conversion is an acid-base neutralization reaction. The resulting salt can then be purified by recrystallization. Another method would be to allow potassium to burn in the presence of chlorine gas, also a very exothermic reaction:
... in dietary food containing potassium chloride, thaumatin added in the ratio of 1 ppm considerably reduces the sensation of bitterness. ...
ATC code A12 Mineral supplements is a therapeutic subgroup of the Anatomical Therapeutic Chemical Classification System, a system of alphanumeric codes developed by the WHO for the classification of drugs and other medical products. Subgroup A12 is part of the anatomical group A Alimentary tract and metabolism.
Codes for veterinary use (ATCvet codes) can be created by placing the letter Q in front of the human ATC code: for example, QA12. ATCvet codes without corresponding human ATC codes are cited with the leading Q in the following list.National issues of the ATC classification may include additional codes not present in this list, which follows the WHO version.Chloride potassium symporter
The potassium chloride symporter is a membrane transport protein that is present in the S3-segment of the renal proximal tubule and in the neuron. It functions in renal chloride reabsorption to transport chloride across the basolateral membrane. The concentrations of K+ and Cl− ions are high inside the cell due to the activities of Na+-K+ pump and NKCC cotransporter, respectively. Hence, their net driving force acting on the K/Cl cotransporter favours the exit of both K+ and Cl− from the cell.
They can lower intracellular chloride concentrations below the electrochemical equilibrium potential.They are of solute carrier family 12.Chloride potassium symporter 4
Potassium-chloride transporter, member 4 is a chloride potassium symporter protein. It is encoded by the gene SLC12A4.Chloride potassium symporter 5
Potassium-chloride transporter member 5 (aka: KCC2 and SLC12A5) is a neuron-specific chloride potassium symporter responsible for establishing the chloride ion gradient in neurons through the maintenance of low intracellular chloride concentrations. It is a critical mediator of synaptic inhibition, cellular protection against excitotoxicity and may also act as a modulator of neuroplasticity. Potassium-chloride transporter member 5 is also known by the names: KCC2 (potassium chloride cotransporter 2) for its ionic substrates, and SLC12A5 for its genetic origin from the SLC12A5 gene in humans.Animals with reduced expression of this transporter exhibit severe motor deficits, epileptiform activity, and spasticity. KCC2 knockout animals, in which KCC2 is completely absent, die postnatally due to respiratory failure.Congener (chemistry)
In chemistry, congeners are related chemical substances "related to each other by origin, structure, or function".Czapek medium
Czapek medium, also called Czapek's agar (CZA) or Czapek-Dox medium, is a growth medium for propagating fungi and other organisms in a laboratory. It was named after its inventors, Polish botanist Friedrich Johann Franz Czapek (May 16, 1868 - July 31, 1921) and American chemist Arthur Wayland Dox (September 19, 1882 - 1954). It was developed to grow Aspergillus niger and Penicillium camemberti. It works well for many saprophytic fungi and soil bacteria such as species of Aspergillus, Candida, Penicillium, and Paecilomyces.
Friedrich Czapek's original recipe is as follows:
1000 g distilled water
30 g cane sugar – energy source and sole source of carbon
1 g monopotassium phosphate – buffering agent
0.5 g magnesium sulfate – source of cations
0.5 g potassium chloride – source of essential ions
0.01 g iron sulfate – source of cations
Arthur Wayland Dox added 2 g of sodium nitrate in his version, to provide a sole source of nitrogen that is inorganic. This makes the medium a selective growth medium as only organisms that can use inorganic nitrogen can grow. Czapek and Dox did not add agar but many recipes add 15 g to make a solid medium.Frumoasa-Tazlău mine
The Frumoasa-Tazlău mine is a large potash mine located in eastern Romania in Bacău County, close to Balcani. Frumoasa-Tazlău represents one of the largest potash reserves in Romania having estimated reserves of 200 million tonnes of ore grading 10% potassium chloride metal.Glucosamine
Glucosamine (C6H13NO5) is an amino sugar and a prominent precursor in the biochemical synthesis of glycosylated proteins and lipids. Glucosamine is part of the structure of the polysaccharides, chitosan, and chitin. Glucosamine is one of the most abundant monosaccharides. It is produced commercially by the hydrolysis of crustacean exoskeletons or, less commonly, by fermentation of a grain such as corn or wheat.
Evidence for the effectiveness of glucosamine as a dietary supplement is mixed. In the United States, it is one of the most common dietary supplements used by adults that is neither a vitamin nor a mineral.Gârcina mine
The Gârcina mine is a large potash mine located in eastern Romania in Neamţ County, close to Gârcina. Gârcina represents one of the largest potash reserves in Romania having estimated reserves of 300 million tonnes of ore grading 10% potassium chloride metal.Ionic crystal
An ionic crystal is a crystal consisting of ions bound together by their electrostatic attraction. Examples of such crystals are the alkali halides, including potassium fluoride, potassium chloride, potassium bromide, potassium iodide, sodium fluoride, and other combinations of sodium, caesium, rubidium, or lithium ions with fluoride, bromide, chloride or iodide ions.
NaCl has a 6:6 co-ordination.
The properties of NaCl reflect the strong interactions that exist between the ions. It is a good conductor of electricity when molten, but very poor in the solid state. When fused the mobile ions carry charge through the liquid.
They are characterized by strong absorption of infrared radiation and have planes along which they cleave easily.
The exact arrangement of ions in an ionic lattice varies according to the size of the ions in the solid.Na-K-Cl cotransporter
The Na-K-Cl cotransporter (NKCC) is a protein that aids in the active transport of sodium, potassium, and chloride into cells. In humans there are two isoforms of this membrane transport protein, NKCC1 and NKCC2, encoded by two different genes (SLC12A2 and SLC12A1 respectively). Two isoforms of the NKCC1/Slc12a2 gene result from keeping (isoform 1) or skipping (isoform 2) exon 21 in the final gene product.NKCC1 is widely distributed throughout the human body; it has important functions in organs that secrete fluids. NKCC2 is found specifically in the kidney, where it serves to extract sodium, potassium, and chloride from the urine so that they can be reabsorbed into the blood.Phosphate-buffered saline
Phosphate-buffered saline (abbreviated PBS) is a buffer solution commonly used in biological research. It is a water-based salt solution containing disodium hydrogen phosphate, sodium chloride and, in some formulations, potassium chloride and potassium dihydrogen phosphate. The buffer helps to maintain a constant pH. The osmolarity and ion concentrations of the solutions match those of the human body (isotonic).Potassium chloride (medical use)
Potassium chloride is used as a medication to treat and prevent low blood potassium. Low blood potassium may occur due to vomiting, diarrhea, or certain medications. The concentrated version should be diluted before use. It is given by slow injection into a vein or by mouth.Side effects may include heart problems if given too quickly by injection into a vein. By mouth it can result in abdominal pain, peptic ulcer disease, or gastrointestinal bleeding. Greater care is recommended in those with kidney problems. As long as high blood potassium does not occur, use in pregnancy or breastfeeding is believed to be safe for the baby. Generally, the strength of the formulation for injection into a vein should not be greater than 40 mmol/l (3 mg/l).Potassium chloride came into large scale commercial use as a fertilizer in 1861 and has been used medically since the 1950s. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. Potassium chloride is available as a generic medication. The wholesale cost in the developing world is about 0.44 USD per 10 ml of 10% solution. In the United Kingdom 10 ml of 15% solution costs the NHS about 0.48 pounds. In 2016 it was the 33rd most prescribed medication in the United States with more than 22 million prescriptions.Potassium hydrosulfide
Potassium hydrosulfide is the inorganic compound with the formula KHS. This colourless salt consists of the cation K+ and the bisulfide anion [SH]−. It is the product of the half-neutralization of hydrogen sulfide with potassium hydroxide. The compound is used in the synthesis of some organosulfur compounds. It is prepared by neutralizing aqueous KOH with H2S. Aqueous solutions of potassium sulfide consist of a mixture of potassium hydrosulfide and potassium hydroxide.
The structure of the potassium hydrosulfide resembles that for potassium chloride. Their structure is however complicated by the non-spherical symmetry of the SH− anions, but these tumble rapidly in the solid high temperatures.Addition of sulfur gives dipotassium pentasulfide.Potassium tetrachloroplatinate
Potassium tetrachloroplatinate(II) is the chemical compound with the formula K2PtCl4. This reddish orange salt is an important reagent for the preparation of other coordination complexes of platinum. It consists of potassium cations and the square planar dianion PtCl42−. Related salts are also known including Na2PtCl4, which is brown-colored and soluble in alcohols, and quaternary ammonium salts, which are soluble in a broader range of organic solvents.Qinghai Salt Lake Potash
Qinghai Salt Lake Potash Company Limited is the largest potash production base in China. It owns a 120-square-kilometer salt lake in Golmud, Qinghai. The company was established and listed on the Shenzhen Stock Exchange in 1997. It specializes in the manufacture and sale of potassium chloride which are distributed under the brand name of "Yanqiao". It is owned by Qinghai Salt Lake Industry Group and Sinochem Corporation.Ringer's lactate solution
Ringer's lactate solution (RL), also known as sodium lactate solution and Hartmann's solution, is a mixture of sodium chloride, sodium lactate, potassium chloride, and calcium chloride in water. It is used for replacing fluids and electrolytes in those who have low blood volume or low blood pressure. It may also be used to treat metabolic acidosis in cases other than those caused by lactic acidosis and to wash the eye following a chemical burn. It is given by injection into a vein or applied to the affected area.Side effects may include allergic reactions, high blood potassium, volume overload, and high blood calcium. It may not be suitable for mixing with certain medications and some recommend against use in the same infusion as a blood transfusion. Ringer's lactate solution has a lower rate of acidosis as compared with normal saline. Use is generally safe in pregnancy and breastfeeding. Ringer's lactate solution is in the crystalloid family of medication. It has the same tonicity as blood.Ringer's solution was invented in the 1880s with lactate being added in the 1930s. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. Lactated Ringer's is available as a generic medication. The wholesale cost in the developing world is about US$0.60 to US$2.30 per liter. For people with poor liver function, Ringer's acetate may be a better alternative with the lactate replaced by acetate. In Scandinavia Ringer's acetate is typically used.Salt substitute
Salt substitutes are low-sodium table salt alternatives marketed to circumvent the risk of high blood pressure and cardiovascular disease associated with a high intake of sodium chloride while maintaining a similar taste. They usually contain mostly potassium chloride, whose toxicity is approximately equal to that of table salt in a healthy person (the LD50 is about 2.5 g/kg, or approximately 190 g for a person weighing 75 kg). Potassium lactate may also be used to reduce sodium levels in food products. It is commonly used in meat and poultry products. The recommended daily allowance of potassium is higher than that for sodium, yet a typical person consumes less potassium than sodium in a given day. Seaweed granules are also marketed as alternatives to salt.However, various diseases and medications may decrease the body's excretion of potassium, thereby increasing the risk of potentially fatal hyperkalemia. People with kidney failure, heart failure, or diabetes should not use salt substitutes without medical advice. A manufacturer, LoSalt, has issued an advisory statement that people taking the following prescription drugs should not use a salt substitute: amiloride, triamterene, Dytac, captopril & other angiotensin-converting enzyme inhibitors, spironolactone, and eplerenone.
Hydrolyzed protein or 5'-nucleotides are sometimes added to potassium chloride to improve the flavour of salt substitutes.
Potassium chloride may have a metallic taste to some.Savage Laboratories
Savage Laboratories is a pharmaceutical research company based in Melville, New York. Its two main products are CroFab—the primary antivenin used to treat rattlesnake and cottonmouth envenomations in the United States—and DigiFab—a treatment for digoxin overdose, both of which are produced by BTG plc but distributed by Savage. It also produces other products such as Ethiodol (a diagnostic agent for use in hysterosalpingography and lymphography), Evac-Q-Kwik (a bowel evacuant), KAON-CL (extended release Potassium chloride), and KAON Elixir-Grape (Potassium gluconate).
Savage Laboratories is a division of Altana AG's American subsidiary, Altana Inc.