{{Chembox | Watchedfields = changed | verifiedrevid = 477003444 | Name = Potassium chlorate | ImageFile = | ImageFile1 = Potassium-chlorate-composition.png | ImageSize1 = 120px | ImageClass1 = skin-invert | ImageName1 = The structure of the ions in potassium chlorate | ImageFile2 = Potassium chlorate-substance.jpg | ImageSize2 = 200px | ImageName2 = Potassium chlorate crystals | OtherNames = {{ubl |Potassium chlorate(V) |Potcrate |Berthollet salt }} | IUPACName = | SystematicName = | Section1 = {{Chembox Identifiers | ChEMBL = 3188561 | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID = 18512 | UNII_Ref = {{fdacite|correct|FDA}} | UNII = H35KS68EE7 | InChI = 1/ClHO3.K/c2-1(3)4;/h(H,2,3,4);/q;+1/p-1 | InChIKey = VKJKEPKFPUWCAS-REWHXWOFAC | SMILES = [K+].[O-]Cl(=O)=O | StdInChI_Ref = {{stdinchicite|correct|chemspider}} | StdInChI = 1S/ClHO3.K/c2-1(3)4;/h(H,2,3,4);/q;+1/p-1 | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | StdInChIKey = VKJKEPKFPUWCAS-UHFFFAOYSA-M | CASNo = 3811-04-9 | CASNo_Ref = {{cascite|correct|CAS}} | PubChem = 6426889 | EINECS = 223-289-7 | RTECS = FO0350000 | UNNumber = 1485 }} | Section2 = {{Chembox Properties | Formula = {{chem2|KClO3}} | Cl=1 |K=1 |O=3 | Appearance = white crystals or powder | Density = {{val|2.32|u=g/cm3}} | MeltingPtC = 356 | BoilingPtC = 400 | BoilingPt_notes = decomposes<ref name=chemister /> | BoilingPt_ref = | Solubility = {{ubl |{{val|3.14|u=g/100g}} ({{cvt|0|C|F K}}) |{{val|4.45|u=g/100g}} ({{cvt|10|C|F K}}) |{{val|8.17|u=g/100g}} ({{cvt|25|C|F K}}) |{{val|13.31|u=g/100g}} ({{cvt|40|C|F K}}) |{{val|55.54|u=g/100g}} ({{cvt|100|C|F K}}) |{{val|183.0|u=g/100g}} ({{cvt|190|C|F K}}) |{{val|2930|u=g/100g}} ({{cvt|330|C|F K}})<ref name=sioc>{{cite book|last1 = Seidell|first1 = Atherton|last2 = Linke|first2 = William F.|year = 1952|title = Solubilities of Inorganic and Organic Compounds|publisher = Van Nostrand |pages=512–513 |url=https://archive.org/details/2ndsolubilitieso00seiduoft/2ndsolubilitieso00seiduoft/page/512/mode/2up |access-date=20 January 2026}}</ref> }} | SolubleOther = negligible in acetone and liquid ammonia<ref name=chemister /> | Solubility1 = {{val|1|u=g/100g}} ({{cvt|20|C|F K}})<ref name=chemister /> | Solvent1 = glycerol | RefractIndex = 1.40835 | MagSus = {{val|-43.8|e=-6|u=cm3/mol}} }} | Section3 = {{Chembox Structure | Coordination = | CrystalStruct = monoclinic }} | Section4 = {{Chembox Thermochemistry | Thermochemistry_ref = <ref name=chemister>{{cite web|url=https://chemister.ru/Databases/Chemdatabase/properties-en.php?dbid=1&id=331|title=Chemister Database - Potassium chlorate|publisher=Chemister |access-date=9 July 2015}}</ref> | DeltaHf = {{val|-391.2|u=kJ/mol}}<ref name=b1>{{cite book| author = Zumdahl, Steven S.|title =Chemical Principles |edition=6th | publisher = Houghton Mifflin Company| year = 2009| isbn = 978-0-618-94690-7|page=A22}}</ref> | Entropy = {{val|142.97|u=J|up=(mol·K)}}<ref name=b1 /> | DeltaGf = {{val|-289.9|u=kJ/mol}} | HeatCapacity = {{val|-391.2|u=J|up=(mol·K)}} }} | Section5 = | Section6 = | Section7 = {{Chembox Hazards | GHS_ref = <ref name="sigma">{{Sigma-Aldrich|sigald|id=255572|title=Potassium chlorate|access-date=1 January 2026}}</ref> | GHSPictograms = {{GHS03}}{{GHS06}} | GHSSignalWord = Danger | HPhrases = {{H-phrases|271|301|401}}<ref name="sigma" /> | PPhrases = {{P-phrases|210|220|221|264|270|273|280|283|301+310+330|306+360|370+378|371+380+375|405|501}}<ref name="sigma" /> | NFPA-H = 3 | NFPA-F = 0 | NFPA-R = 3 | NFPA-S = OX | NFPA_ref = <ref name="FisherSDS">{{cite web |title=SDS - Potassium chlorate |url=https://www.fishersci.com/store/msds?partNumber=P212100&productDescription=POTASSIUM+CHLORATE+CERT+100GM&vendorId=VN00033897&countryCode=US&language=en |website=www.fishersci.com |publisher=ThermoFisher Scientific |format=pdf |access-date=20 January 2026 |pages=3,5 |date=18 December 2025}}</ref><!-- I found other values for these on a different SDS from Fisher, far lower values on an SDS from flinn sci, etc... I'm using the most recent / highest since the actual NFPA's info isn't available readily --> | LD50 = {{val|100|u=mg/kg}} (oral, rat)<ref name="FisherSDS"/> | LC50 = >{{val|5.1|u=mg/L}}<ref name="FisherSDS"/> }} | Section8 = {{Chembox Related | OtherAnions = {{ubl |Potassium bromate |Potassium chloride |Potassium chlorite |Potassium hypochlorite |Potassium iodate |Potassium nitrate |Potassium perchlorate }} | OtherCations = {{ubl |Ammonium chlorate |Sodium chlorate |Barium chlorate }} }} }}
'''Potassium chlorate''' is the inorganic compound with the molecular formula KClO<sub>3</sub>. In its pure form, it is a white solid. After sodium chlorate, it is the second most common chlorate in industrial use. It is a strong oxidizing agent and its most important application is in safety matches.<ref name="ullmann_2000">{{Ullmann |last1=Vogt |first1=Helmut |last2=Balej |first2=Jan |last3=Bennett |first3=John E. |last4=Wintzer |first4=Peter |last5=Sheikh |first5=Saeed Akbar |last6=Gallone |first6=Patrizio |date=15 June 2000 |title=Chlorine Oxides and Chlorine Oxygen Acids |doi=10.1002/14356007.a06_483}}</ref>
==Production== thumb|left|100px|The crystal structure of potassium chlorate. Color code: red = O, violet = K, green = Cl
On the industrial scale, potassium chlorate is produced by the salt metathesis reaction of sodium chlorate and potassium chloride:
: {{Chem2 | NaClO3 + KCl -> NaCl + KClO3 }}
The reaction is driven by the low solubility of potassium chlorate in water. The equilibrium of the reaction is shifted to the right hand side by the continuous precipitation of the product (Le Chatelier's Principle). The precursor sodium chlorate is produced industrially in very large quantities by electrolysis of sodium chloride, common table salt.<ref name="ullmann_2000"/>
The direct electrolysis of KCl in aqueous solution is also used sometimes, in which elemental chlorine formed at the anode reacts with KOH ''in situ''. The low solubility of {{chem2|KClO3}} in water causes the salt to conveniently isolate itself from the reaction mixture by simply precipitating out of solution.
Potassium chlorate can be produced in small amounts by disproportionation in a sodium hypochlorite solution followed by metathesis reaction with potassium chloride:{{cn|date=January 2026}}
: {{Chem2 | 3 NaOCl -> 2 NaCl + NaClO3 }} : {{Chem2 | KCl + NaClO3 -> NaCl + KClO3 }}
It can also be produced by passing chlorine gas into a hot solution of potassium hydroxide:<ref name="Pradyot Patnaik 2002">{{cite book |last1=Patnaik |first1=Pradyot |title=Handbook of inorganic chemicals |date=2003 |publisher=McGraw-Hill |location=New York, NY |isbn=0-07-049439-8}}</ref>{{page needed|date=January 2026}}
: {{Chem2 | 3 Cl2 + 6 KOH -> KClO3 + 5 KCl + 3 H2O }}
==Uses== {{more references needed section|date=July 2025}} thumb|left|Potassium chlorate burning sugar
Potassium chlorate was one key ingredient in early firearms percussion caps (primers).<ref>{{Cite book |last=Parkes |first=Samuel |url=http://archive.org/details/chemicalcatechi02parkgoog |title=The chemical catechism : with notes, illustrations, and experiments |date=1818 |publisher=New York : Collins and Co. |others=Harvard University}}</ref>
Another application of potassium chlorate is as the oxidizer in smoke compositions such as those used in smoke grenades.<ref>{{cite tech report |title=Encyclopedia of Explosives and Related Items |volume=6, Etagenguss to Gyroscopic Movement of Projectiles |chapter=G - Grenades |page=G139 |first1=Basil T. |last1=Fedoroff |first2=Oliver E. |last2=Sheffield |date=1 January 1974 |publisher=U.S. Army Research and Development Command TACOM - Ardec Warheads, Energetics and Combat Support Center |location=Picatinny Arsenal, Dover, NJ |url=https://apps.dtic.mil/sti/pdfs/ADA011845.pdf#page=781 |id=ADA011845, PATR2700 |lccn=61-61759}}</ref>
=== Laboratory uses and demonstrations === Potassium chlorate readily decomposes if heated while in contact with a catalyst, typically manganese(IV) dioxide ({{chem2|MnO2}}).<ref>{{Cite web |title=Manganese dioxide, reaction with potassium chlorate - Big Chemical Encyclopedia |url=https://chempedia.info/info/manganese_dioxide_reaction_with_potassium_chlorate/ |access-date=2026-03-11 |website=chempedia.info}}</ref> Thus, it may be simply placed in a test tube and heated over a burner. If the test tube is equipped with a one-holed stopper and hose, warm oxygen can be drawn off. The reaction is as follows:
: {{Chem2 | 2 KClO3(s) + MnO2(cat) -> 3 O2(g) + 2 KCl(s) }}
Heating it in the absence of a catalyst converts it into potassium perchlorate:<ref name="Pradyot Patnaik 2002"/>{{page needed|date=January 2026}}
: {{Chem2 | 4 KClO3 -> 3 KClO4 + KCl }}
With further heating, potassium perchlorate decomposes to potassium chloride and oxygen:
: {{Chem2 | KClO4 -> KCl + 2 O2 }}
The safe performance of this reaction requires very pure reagents and careful temperature control. Molten potassium chlorate is an extremely powerful oxidizer and spontaneously reacts with many common materials such as sugar. Explosions have resulted from liquid chlorates spattering into the latex or PVC tubes of oxygen generators and from contact between chlorates and hydrocarbon sealing greases. Impurities in potassium chlorate itself can also cause problems.
Potassium chlorate reacts with sulfuric acid to form highly reactive chlorine dioxide, potassium sulfate, oxygen, and water:<ref name=Pauling>{{cite book |page=264|last=Linus Pauling |title=General chemistry |publisher=W.H. Freeman and Company Publishing |edition=2nd |location=United States |year=1953 |url=https://archive.org/details/dli.ernet.448871/page/269/mode/2up }}</ref>
: {{Chem2 | 4 KClO3 + 2 H2SO4 -> 2 K2SO4 + 4 ClO2 (g) + O2 (g) + 2 H2O }}
Chlorine dioxide, combined with oxygen gas (and any remaining potassium chlorate) is sufficiently reactive that it spontaneously ignites if combustible material (sugar, paper, etc.) is present.{{cn|date=January 2026}}
thumb|left|Candy being dropped into molten salt
In schools, molten potassium chlorate is used in screaming jelly babies, Gummy bear, Haribo, and Trolli candy demonstration where the candy is dropped into the molten salt.<ref name="Education in Chemistry-2021">{{Cite web |date=January 2021 |title=Screaming jelly baby – technician notes |url=https://edu.rsc.org/download?ac=509818 |access-date=December 6, 2021 |website=Education in Chemistry |archive-url=https://web.archive.org/web/20250912142223/https://edu.rsc.org/download?ac=509818 |archive-date=2025-09-12}}</ref>
=== Agriculture === Potassium chlorate is used also as a pesticide. In Finland it was sold under trade name Fegabit.{{cn|date=January 2026}}
Potassium chlorate is used to force the blossoming stage of the longan tree, causing it to produce fruit in warmer climates.<ref>{{cite journal |last1=Manochai |first1=P. |last2=Sruamsiri |first2=P. |last3=Wiriya-alongkorn |first3=W. |last4=Naphrom |first4=D. |last5=Hegele |first5=M. |last6=Bangerth |first6=F. |title=Year around off season flower induction in longan (Dimocarpus longan, Lour.) trees by KClO3 applications: potentials and problems |journal=Scientia Horticulturae |date=May 2005 |volume=104 |issue=4 |pages=379–390 |doi=10.1016/j.scienta.2005.01.004}}</ref><ref>{{cite journal |last1=Manochai |first1=P. |last2=Jaroenkit |first2=T. |last3=Ussahatanonta |first3=S. |last4=Ongprasert |first4=S. |last5=Kativat |first5=B. |title=Seasonal Effect Of Potassium Chlorate On Flowering And Yield Of Longan (Dimocarpus Longan Lour.) |journal=Acta Horticulturae |date=May 2010 |issue=863 |pages=363–366 |doi=10.17660/ActaHortic.2010.863.48}}</ref>
===Illicit use=== Militant groups in Afghanistan also use potassium chlorate extensively as a key component in the production of improvised explosive devices (IEDs). When significant effort was made to reduce the availability of ammonium nitrate fertilizer in Afghanistan, IED makers started using potassium chlorate as a cheap and effective alternative. In 2013, 60% of IEDs in Afghanistan used potassium chlorate, making it the most common ingredient used in IEDs.<ref>{{cite news|url=https://www.usatoday.com/story/news/world/2013/06/25/ammonium-nitrate-potassium-chlorate-ieds-afghanistan/2442191/ |title=Afghan bomb makers shifting to new explosives for IEDs |publisher=USAToday.com |date= June 25, 2013|access-date=2013-06-25}}</ref> Potassium chlorate was also the main ingredient in the car bomb used in the 2002 Bali bombings that killed 202 people.<ref>{{Cite book |last1=Asthana |first1=N. C. |url=https://books.google.com/books?id=8EqWnqdsgZMC&pg=PA263 |title=Urban Terrorism: Myths and Realities |last2=Nirmal |first2=Anjali |date=2009 |publisher=Pointer Publishers |isbn=978-81-7132-598-6 |language=en}}</ref>
==Safety== Potassium chlorate is a very powerful oxidizer. It reacts vigorously, and in some cases spontaneously ignites or explodes, when mixed with many combustible materials. It burns vigorously in combination with virtually any combustible material, even those normally only slightly flammable (including ordinary dust and lint). Mixtures of potassium chlorate and a fuel can ignite on contact with sulfuric acid. Mixtures of potassium chlorate with lactose,<ref name="PyroChemistry">{{cite book |last1=Jennings-White |first1=C. |last2=Kosanke |first2=K. L. |title=Pyrotechnic Chemistry |edition=1.1 |isbn=978-1-889526-31-7 |location=Whitewater, CO, USA |publisher=Journal of Pyrotechnics |date=2013 |page=18-4 |url=http://www.jpyro.co.uk/wp-content/uploads/bk2022h.pdf?page=390 |chapter=18 - Hazardous Chemical Combinations: A Discussion}}</ref> sulfur,<ref name="PyroChemistry"/>{{rp|18-5}} sulfides such as antimony(III) sulfide,<ref name="PyroChemistry"/>{{rp|18-5}} or phosphorus are extremely shock and friction sensitive.
==See also== * Chloric acid
==References== {{Reflist}}
==External links== {{Commons category|Potassium chlorate}}
{{Potassium compounds}} {{Chlorates}}
Category:Chlorates Category:Potassium compounds Category:Pyrotechnic oxidizers