Chemical decomposition

Chemical decomposition, analysis or breakdown is the separation of a chemical compound into elements or simpler compounds. It is sometimes defined as the exact opposite of a chemical synthesis. Chemical decomposition is often an undesired chemical reaction. The stability of a chemical compound is eventually limited when exposed to extreme environmental conditions like heat, radiation, humidity, or the acidity of a solvent. The details of a decomposition process, where a molecule may break up into a host of smaller fragments, are not generally well defined. Chemical decomposition is exploited in several analytical techniques, notably mass spectrometry, traditional gravimetric analysis, and thermogravimetric analysis.

Another, broader definition of the term decomposition includes the breakdown of one phase into two or more phases.

There are six types of decomposition reactions, three of which are considered the three broad types.The three latter (broad) types discussed here are thermal, electrolytic, and catalytic.

The generalized reaction for chemical decomposition is:

An example is the electrolysis of water to the gases hydrogen and oxygen:

An example of spontaneous decomposition is that of hydrogen peroxide, which will slowly decompose into water and oxygen:

Carbonates will decompose when heated, a notable exception being carbonic acid, H₂CO₃. Carbonic acid (commonly seen as the "fizz" in carbonated beverages) will spontaneously (with no addition of an external energy source) decompose over time into carbon dioxide and water

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