Editing Potassium chloride (section)

==Chemical properties==

===Solubility===
KCl is soluble in a variety of polar solvents.
{| class="wikitable" style="margin: 1em;"
|+ Solubility<ref>{{cite book| vauthors = Burgess J |title=Metal Ions in Solution|publisher=Ellis Horwood|place=New York|year=1978|isbn=978-0-85312-027-8}}{{page needed|date=July 2015}}</ref>
! Solvent !! Solubility<br>(g/kg of solvent at 25&nbsp;°C)
|-
| [[Water (molecule)|Water]] || 360
|-
| [[Ammonia|Liquid ammonia]] || 0.4
|-
| [[Sulfur dioxide|Liquid sulfur dioxide]] || 0.41
|-
| [[Methanol]] || 5.3
|-
| [[Ethanol]] || 0.37
|-
| [[Formic acid]] || 192
|-
| [[Sulfolane]] || 0.04
|-
| [[Acetonitrile]] || 0.024
|-
| [[Acetone]] || 0.00091
|-
| [[Formamide]] || 62
|-
| [[Acetamide]] || 24.5
|-
| [[Dimethylformamide]] || 0.17–0.5
|}

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 {{chem2|K+}} and {{chem2|Cl-}} ions.

===Redox and the conversion to potassium metal===
Although potassium is more [[electropositive]] than [[sodium]], KCl can be reduced to the metal by reaction with metallic sodium at 850&nbsp;°C because the more volatile potassium can be removed by distillation (see [[Le Chatelier's principle]]):
:{{chem2 | KCl_{(l)} + Na_{(l)} <-> NaCl_{(l)} + K_{(g)} }}

This method is the main method for producing metallic potassium. [[Electrolysis]] (used for sodium) fails because of the high solubility of potassium in molten KCl.<ref name=Ullmann>{{cite book | vauthors = Burkhardt ER |chapter=Potassium and Potassium Alloys |year=2006 |title=Ullmann's Encyclopedia of Industrial Chemistry |doi=10.1002/14356007.a22_031.pub2|isbn=978-3-527-30673-2 }}</ref>
{{clear}}

===Other potassium chloride stoichiometries===
Potassium chlorides with formulas other than KCl have been predicted to become stable under pressures of 20 GPa or more.<ref>{{Cite journal|last1=Zhang|first1=Weiwei|last2=Oganov|first2=Artem R.|last3=Zhu|first3=Qiang|last4=Lobanov|first4=Sergey S.|last5=Stavrou|first5=Elissaios|last6=Goncharov|first6=Alexander F.|title=Stability of numerous novel potassium chlorides at high pressure|journal=Sci Rep|volume=6|page=26265|date=23 May 2016|doi=10.1038/srep26265|pmid=27211847 |pmc=4876327|bibcode=2016NatSR...626265Z }}</ref> Among these, two phases of KCl<sub>3</sub> were synthesized and characterized. At 20-40 GPa, a trigonal structure containing K<sup>+</sup> and Cl<sub>3</sub><sup>−</sup> is obtained; above 40 GPa this gives way to a phase isostructural with the intermetallic compound Cr<sub>3</sub>Si.{{citation needed|date=December 2024}}