saturation, of an organic compound, condition occurring when its molecules contain no double or triple bonds and thus cannot undergo addition reactions. For example, ethane (H₃C-CH₃) is a saturated compound. A compound is called unsaturated if it can undergo addition reactions. In the unsaturated compound ethene (H₂C--CH₂), the carbon-carbon double bond readily reacts, e.g., with hydrogen to form ethane.

saturation, of a solution: see solution.

State of an organic compound in which all its carbon atoms are linked by single covalent bonds. Saturation also means the state of a solution or vapour (see vaporization) in which it has the highest possible concentration of the dissolved or vaporized material at a given pressure and temperature. Though it is sometimes possible to bring about supersaturation (a concentration exceeding the equilibrium value), such solutions or vapours are unstable and spontaneously revert to the saturated state, accompanied by the transformation of the excess material to the solid or liquid form (precipitation). Seealso fatty acid; hydrogenation.

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