Unsaturated Definition in Chemistry

The Two Meanings of Unsaturated

Hand holding a beaker with a chemical solution.

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In chemistry, the term "unsaturated" usually refers to one of two things: When referring to chemical solutions, an unsaturated solution is able to dissolve more solute. In other words, the solution is not saturated. An unsaturated solution is more dilute than a saturated solution.

When referring to organic compounds, unsaturated means a molecule contains double or triple carbon-carbon bonds. Examples of unsaturated organic molecules include HC=CH and H2C=O. In this context, being saturated can be thought of as being "saturated with hydrogen atoms."

Saturation can also refer to the percentage of protein binding sites that are filled or the lack of susceptibility of an organometallic compound to oxidative addition. Whenever the term "saturation" is used in chemistry, it refers to whether a phenomenon is close to maximum capacity.

Source

  • Badertscher, M.; Bischofberger, K.; Munk, M.E.; Pretsch, E. (2001). "A Novel Formalism To Characterize the Degree of Unsaturation of Organic Molecules". Journal of Chemical Information and Modeling. 41 (4): 889. doi: 10.1021/ci000135o