Potassium perchlorate

From Sciencemadness Wiki
Jump to: navigation, search
Potassium perchlorate
Potassium perchlorate.jpg
Potassium perchlorate is a white solid
IUPAC name
Potassium perchlorate
Other names
Potassium chlorate(VII)
Molar mass 138.55 g/mol
Appearance White crystalline solid
Odor Odorless
Density 2.5239 g/cm3
Melting point 610 °C (1,130 °F; 883 K)
Boiling point Decomp. starts at 400 °C
0.76 g/100 ml (0 °C)
1.5 g/100 ml (25 °C)
4.76 g/100 ml (40 °C)
21.08 g/100 ml (100 °C)
Solubility Reacts with sulfuric acid
Insoluble in alcohols, diethyl ether, toluene, xylene
Vapor pressure ~0 mmHg
Safety data sheet Sigma-Aldrich
Flash point Non-flammable
Related compounds
Related compounds
Potassium hypochlorite
Potassium chlorite
Potassium chlorate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Potassium perchlorate is the inorganic salt with the chemical formula KClO4.



Just like any perchlorate, this salt is a strong oxidizer and reacts violently with many organic substances at elevated temperatures.

It reacts with a strong acid, such as sulfuric acid, to release perchloric acid.

KClO4 + H2SO4 → KHSO4 + HClO4


Potassium perchlorate is a colorless, crystalline solid salt. It has the lowest solubility in water of any alkali perchlorate, 1.5 g / 100 ml water at 25 °C. It is not hygroscopic and does not form hydrates.


Potassium perchlorate can be found in certain antithyroid medications, albeit the quantity is small. The sale of potassium perchlorate is regulated in most countries due to its powerful oxidizing properties.


Potassium perchlorate can be prepared by reacting a potassium salt, usually potassium chloride with sodium perchlorate. Potassium perchlorate will precipitate due to its low solubility. Filter and dry the perchlorate precipitate. It may be beneficial to heat the solution after mixing the potassium salt with the perchlorate. After cooling the potassium perchlorate forms somewhat bigger crystals that are easier to deal with than a fine powder.

While KClO4 can also be prepared by electrolysis of potassium chloride in water, the yield is very poor, due to its low solubility, as well as the low solubility of its precursor, potassium chlorate.




Potassium perchlorate is a powerful oxidizer. When handling it, it should be kept away from any open flame as well as organic substances. Unlike the chlorate salt, perchlorate mixtures with sulfur are stable.

It is moderately toxic, in large amounts it interferes with iodine uptake into the thyroid gland.


Potassium perchlorate must be stored away from any strong mineral acid as well as any reducing agent, in sealed bottles. As it is not hygroscopic, it does not require dry environment. Any clean plastic bottle can be used as storage container.


Potassium perchlorate can be neutralized by reacting it with a reducing agent. This, however, only can be done at elevated temperatures.

Perchlorates can be destroyed with metallic iron under UV light, in the absence of air.[1]


  1. Perchlorate in the Environment (2000), Edward Todd Urbansky, pag. 106

Relevant Sciencemadness threads