Saturated Definition in Chemistry

What Does Saturated Mean in Chemistry?

Ethane is an example of an unsaturated compound.
Ethane is an example of an unsaturated compound. GIPhotoStock / Getty Images

The terms "saturated" and "saturation" may have different meanings in chemistry, depending on the context in which they are used. Here are the three most common definitions:

Saturated Definition #1

This chemistry definition refers to a saturated compound. A saturated substance is one in which the atoms are linked by single bonds. A fully saturated compound contains no double or triple bonds. Alternatively, if a molecule contains double or triple bonds, it is considered to be unsaturated.

Example: ethane (C2H6) is a saturated hydrocarbon that has no double or triple bonds, while ethylene has a C=C double bond and ethyne has a carbon-carbon triple bond. An organometallic complex is said to be unsaturated if it has fewer than 18 valence electrons and is therefore exposed to oxidative coordinate or addition of another ligand.

Saturated Definition #2

This definition refers to a saturated solution. In this context, saturated refers to a point of maximum concentration, in which no more solute may be dissolved in a solvent. Saturation, in this context, depends on temperature and pressure. Usually, raising the temperature allows a solution to dissolve more solute.

Example: When you grow crystals from an aqueous (water) solution, you dissolve as much solute into the water as you can, to the point where no more will dissolve. This produces a saturated solution.

Saturated Definition #3

Although not a technical chemistry definition, saturated may mean thoroughly soaked with as much water or other solvent as possible.

Example: If a protocol asks you to completely saturate a filter paper with solution, this means to thoroughly wet it. If an atmosphere is at its highest humidity level for a given temperature, it is saturated with water vapor.