Potassium chlorate

Potassium chlorate

The structure of the ions in potassium chlorate
Potassium chlorate crystals
Names
Other names Potassium chlorate(V) Potcrate Berthollet salt
Identifiers
CAS Number	3811-04-9  Y
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL3188561
ChemSpider	18512  Y
ECHA InfoCard	100.021.173
EC Number	223-289-7
PubChem CID	6426889
RTECS number	FO0350000
UNII	H35KS68EE7  Y
UN number	1485
CompTox Dashboard (EPA)	DTXSID6047448
InChI InChI=1S/ClHO3.K/c2-1(3)4;/h(H,2,3,4);/q;+1/p-1 Y Key: VKJKEPKFPUWCAS-UHFFFAOYSA-M Y InChI=1/ClHO3.K/c2-1(3)4;/h(H,2,3,4);/q;+1/p-1 Key: VKJKEPKFPUWCAS-REWHXWOFAC
SMILES [K+].[O-]Cl(=O)=O
Properties
Chemical formula	KClO3
Molar mass	122.55 g·mol−1
Appearance	white crystals or powder
Density	2.32 g/cm3
Melting point	356 °C (673 °F; 629 K)
Boiling point	400 °C (752 °F; 673 K) decomposes [1]
Solubility in water	3.14 g/100g (0 °C (32 °F; 273 K)) 4.45 g/100g (10 °C (50 °F; 283 K)) 8.17 g/100g (25 °C (77 °F; 298 K)) 13.31 g/100g (40 °C (104 °F; 313 K)) 55.54 g/100g (100 °C (212 °F; 373 K)) 183.0 g/100g (190 °C (374 °F; 463 K)) 2930 g/100g (330 °C (626 °F; 603 K)) [2]
Solubility	negligible in acetone and liquid ammonia [1]
Solubility in glycerol	1 g/100g (20 °C (68 °F; 293 K)) [1]
Magnetic susceptibility (χ)	−43.8×10−6 cm3/mol
Refractive index (nD)	1.40835
Structure
Crystal structure	monoclinic
Thermochemistry [1]
Heat capacity (C)	−391.2 J/(mol·K)
Std molar entropy (S⦵298)	142.97 J/(mol·K) [3]
Std enthalpy of formation (ΔfH⦵298)	−391.2 kJ/mol [3]
Gibbs free energy (ΔfG⦵)	−289.9 kJ/mol
Hazards
GHS labelling: [4]
Pictograms
Signal word	Danger
Hazard statements	H271, H301, H401 [4]
Precautionary statements	P210, P220, P221, P264, P270, P273, P280, P283, P301+P310+P330, P306+P360, P370+P378, P371+P380+P375, P405, P501 [4]
NFPA 704 (fire diamond)	[5] 3 0 3 OX
Lethal dose or concentration (LD, LC):
LD50 (median dose)	100 mg/kg (oral, rat) [5]
LC50 (median concentration)	>5.1 mg/L [5]
Related compounds
Other anions	Potassium bromate Potassium chloride Potassium chlorite Potassium hypochlorite Potassium iodate Potassium nitrate Potassium perchlorate
Other cations	Ammonium chlorate Sodium chlorate Barium chlorate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y  verify  (what is  YN ?) Infobox references

Potassium chlorate is the inorganic compound with the molecular formula KClO₃. 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. ^[6]

Production

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:

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. ^[6]

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 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:^{[ citation needed ]}

3 NaOCl → 2 NaCl + NaClO₃

KCl + NaClO₃ → NaCl + KClO₃

It can also be produced by passing chlorine gas into a hot solution of caustic potash: ^{[7] [ page needed ]}

3 Cl₂ + 6 KOH → KClO₃ + 5 KCl + 3 H₂O

Uses

Potassium chlorate burning sugar

Potassium chlorate was one key ingredient in early firearms percussion caps (primers). ^[8]

Another application of potassium chlorate is as the oxidizer in smoke compositions such as those used in smoke grenades. ^[9]

Laboratory uses and demonstrations

Potassium chlorate readily decomposes if heated while in contact with a catalyst, typically manganese(IV) dioxide (MnO₂). 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:

2 KClO₃(s) + MnO₂(cat) → 3 O₂(g) + 2 KCl(s)

Heating it in the absence of a catalyst converts it into potassium perchlorate: ^{[7] [ page needed ]}

4 KClO₃ → 3 KClO₄ + KCl

With further heating, potassium perchlorate decomposes to potassium chloride and oxygen:

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: ^[10]

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.^{[ citation needed ]}

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. ^[11]

Agriculture

Potassium chlorate is used also as a pesticide. In Finland it was sold under trade name Fegabit.^{[ citation needed ]}

Potassium chlorate is used to force the blossoming stage of the longan tree, causing it to produce fruit in warmer climates. ^{[12] [13]}

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. ^[14] Potassium chlorate was also the main ingredient in the car bomb used in the 2002 Bali bombings that killed 202 people. ^[15]

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, ^[16] sulfur, ^{[16] : 18–5} sulfides such as antimony(III) sulfide, ^{[16] : 18–5} or phosphorus are extremely shock and friction sensitive.

See also

• Chloric acid

References

1. "Chemister Database - Potassium chlorate". Chemister. Retrieved 9 July 2015.
2. Seidell, Atherton; Linke, William F. (1952). Solubilities of Inorganic and Organic Compounds. Van Nostrand. pp. 512–513. Retrieved 20 January 2026.
3. Zumdahl, Steven S. (2009). Chemical Principles (6th ed.). Houghton Mifflin Company. p. A22. ISBN   978-0-618-94690-7.
4. Sigma-Aldrich Co., product no. 255572.
5. "SDS - Potassium chlorate" (pdf). www.fishersci.com. ThermoFisher Scientific. 18 December 2025. pp. 3, 5. Retrieved 20 January 2026.
6. Vogt, Helmut; Balej, Jan; Bennett, John E.; Wintzer, Peter; Sheikh, Saeed Akbar; Gallone, Patrizio (15 June 2000). "Chlorine Oxides and Chlorine Oxygen Acids". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a06_483. ISBN   978-3-527-30673-2.
7. Patnaik, Pradyot (2003). Handbook of inorganic chemicals. New York, NY: McGraw-Hill. ISBN   0-07-049439-8.
8. Parkes, Samuel (1818). The chemical catechism : with notes, illustrations, and experiments. Harvard University. New York : Collins and Co.
9. Fedoroff, Basil T.; Sheffield, Oliver E. (1 January 1974). "G - Grenades". Encyclopedia of Explosives and Related Items (PDF) (Technical report). Vol. 6, Etagenguss to Gyroscopic Movement of Projectiles. Picatinny Arsenal, Dover, NJ: U.S. Army Research and Development Command TACOM - Ardec Warheads, Energetics and Combat Support Center. p. G139. LCCN   61-61759. ADA011845, PATR2700.
10. Linus Pauling (1953). General chemistry (2nd ed.). United States: W.H. Freeman and Company Publishing. p. 264.
11. "Screaming jelly baby – technician notes". Education in Chemistry. January 2021. Archived from the original on 2025-09-12. Retrieved December 6, 2021.
12. Manochai, P.; Sruamsiri, P.; Wiriya-alongkorn, W.; Naphrom, D.; Hegele, M.; Bangerth, F. (May 2005). "Year around off season flower induction in longan (Dimocarpus longan, Lour.) trees by KClO3 applications: potentials and problems". Scientia Horticulturae. 104 (4): 379–390. doi:10.1016/j.scienta.2005.01.004.
13. Manochai, P.; Jaroenkit, T.; Ussahatanonta, S.; Ongprasert, S.; Kativat, B. (May 2010). "Seasonal Effect Of Potassium Chlorate On Flowering And Yield Of Longan (Dimocarpus Longan Lour.)". Acta Horticulturae (863): 363–366. doi:10.17660/ActaHortic.2010.863.48.
14. "Afghan bomb makers shifting to new explosives for IEDs". USAToday.com. June 25, 2013. Retrieved 2013-06-25.
15. Asthana, N. C.; Nirmal, Anjali (2009). Urban Terrorism: Myths and Realities. Pointer Publishers. ISBN   978-81-7132-598-6.
16. Jennings-White, C.; Kosanke, K. L. (2013). "18 - Hazardous Chemical Combinations: A Discussion". Pyrotechnic Chemistry (PDF) (1.1 ed.). Whitewater, CO, USA: Journal of Pyrotechnics. p. 18-4. ISBN   978-1-889526-31-7.