Potassium chloride is an inorganic compound from the group of halides, chemically described as the potassium salt of Hydrochloric Acid. In this substance, potassium exists as positively charged K⁺ cations and chlorine as negatively charged chloride anions Cl^-.

Names and Identifiers

Chemical formulas

Molecular formula and structural formula of Potassium chloride:

Data and Properties

Potassium Chloride Solution

Solid potassium chloride is readily soluble in water, depending on the temperature:

A completely saturated potassium chloride solution is obtained at 20 °C by dissolving 339.7 grams of KCl in one liter of water. The boiling point of this solution is 108.6 °C, and its density is 1.18 g/cm³.

The following table shows some data and properties (molar concentration c, mass concentration β, density ρ, refractive index nD) of aqueous potassium chloride solutions as a function of the mass fraction of KCl. The values ​​are valid for a temperature of 20 °C.

Electrolyte solutions containing potassium chloride, such as Ringer´s solution, are used in medicine and contain 4 to 5 mmol/L potassium ions.

A 3 molar or 3M KCl solution (c = 3 mol/l) serves as a storage solution for many types of pH electrodes and ORP probes; the solution is obtained from 223.644 g of potassium chloride in a volumetric flask and making up the volume to one liter with distilled water.

The relative humidity above a saturated KCl solution in a container is a constant 85% at 23°C.

Conductivity

Potassium chloride solutions conduct electricity depending on temperature and concentration. They are used - along with other salt solutions - for calibrating conductivity meters. The electrical conductivity (conductance values ​​κ in millisiemens per cm) of various KCl solutions are shown in the following tables.

The first table lists the conductivity of a potassium chloride solution as a function of the mass percent of KCl in the aqueous solution; all values ​​apply to a temperature of 20 °C:

The second table lists typical values ​​for preparing a calibration solution (in grams of KCl per liter of pure distilled water). The data refers to a temperature of 25 °C.

Percentage and isotopic composition:

Mass-related elemental composition and isotope proportions of the compound Potassium chloride - ClK - calculated based on molecular mass.

*) The third column lists the atomic masses or isotope masses of the elements involved and - in square brackets - the natural isotope composition.

More calculated data

The molar mass is M = 74.5483 grams per mole.

The amount of substance in one kilogram of the substance is n = 13.414 mol.

The amount of substance in one gram of the substance is n = 0.013 mol.

Monoisotopic mass: 73.932559185 Da - related to ³⁵Cl³⁹K.

Potassium chloride as Active Ingredient

Use in food

Use in Cosmetics

External Sources

Manufacturers and Sources of Supply

The table below lists producers and suppliers of Potassium chloride as a commercial chemical for laboratories, research, industry and production with the corresponding contact details.

Literature Sources

[0] - Specialist and research articles in scientific journals via PubMed: Potassium_chloride.

[1] - Maged Younes, Gabriele Aquilina, Laurence Castle et al.:
Re‐evaluation of hydrochloric acid (E 507), potassium chloride (E 508), calcium chloride (E 509) and magnesium chloride (E 511) as food additives.
In: EFSA Journal, (2019), DOI 10.2903/j.efsa.2019.5751.

Last update: 2026-01-07

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