Potassium chlorate

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Potassium chlorate

General
Other names	Potassium chlorate(V)
Molecular formula	K</sub>ClO₃
Molar mass	122.55 g/mol
Appearance	white solid
CAS number	[3811-04-9]
Properties
Density and phase	2.32 g/cm³, solid
Solubility in water	7.3 g/100 ml (20 °C)
Melting point	356 °C
Boiling point	~400 °C decomp.
Structure
Coordination geometry	?
Crystal structure	?
Hazards
MSDS	External MSDS
EU classification	Oxidant (O) Harmful (Xn) Dangerous for the environment (N)
NFPA 704	Template:Nfpa
R-phrases	R9, R22, R51/53
S-phrases	S2, S13, S17, S46, S61
Flash point	none
Supplementary data page
Structure and properties	n, ε_r, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Related compounds
Other anions	Potassium bromate Potassium iodate
Other cations	Ammonium chlorate Sodium chlorate
Related compounds	Potassium chloride Potassium hypochlorite Potassium chlorite Potassium perchlorate
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Potassium chlorate is a compound containing potassium, chlorine and oxygen. In pure form, it is a white crystalline substance. It is the most common chlorate in industrial use, and is usually present in well-stocked laboratories.

Used as:

Potassium chlorate should be handled with care. It reacts vigorously and in some cases spontaneously ignites or explodes when mixed with many combustible materials. It is used in some recipes for gunpowder, generally replacing the less powerful ingredient potassium nitrate. Although chlorate-based propellants are more efficent than traditional gunpowder and are less susceptible to damage by water, they can be unstable and are much more expensive. Chlorate propellants must only be used in equipment designed for them; failure to follow this precaution is a common source of accidents.

When mixed with other materials it forms a high explosive. The slightly weaker sodium chlorate is used as a substitute for potassium chlorate. In World War I Potassium Chlorate was the most common type of plastic explosive used, often filling grenades and other munitions. When used in explosives as an oxidizer, the explosive is low order meaning it burns rapidly rather than explodes. When mixed with a plastifier it becomes a high order, requiring a blasting cap (generally a commercial #8) to detonate.

Potassium Chlorate is often used in highschool and college laboratories to generate oxygen gas; it is a far cheaper source than a pressurized or cryogenic oxygen tank. Potasium Chlorate will readily decompose if heated in contact with an oxidizer, typically Manganese (IV) Oxide. 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 ==Heat==> 3 O2 (gas) + 2 KCl (ionic solid)

The safe performance of this reaction requires very pure reagents and careful temperature control. Molten potassium chlorate is an extremely powerful oxidizer and will spontaneously react with many common materials. Explosions have resulted from liquid chlorates spattering into the latex or PVC tubes of oxygen generators, as well as from contact between chlorates and hydrocarbon sealing greases. Impurities in potassium chlorate itself can also cause problems. When working with a new batch of potassium chlorate, it is advisible to take a small sample (~ 1 gram) and heat it strongly on an open glass plate. Contamination may cause this small quantity to explode, indicating that the chlorate should be discarded. Potassium chlorate is used in the oxygen-supply systems of aircraft, and has been responsible for at least one plane crash. A fire on the space station MIR was also traced to this substance.

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