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Meso compound

A meso compound or meso isomer is a chemical compound whose molecules contain 2 or more asymmetric atoms (stereocenters) but it is optically inactive (or achiral) because it contains an internal plane of symmetry.

For example one of the isomers of tartaric acid depicted below is a meso compound. An internal mirror plane exists bisecting the molecule; on rotating the molecule 180° on a plane perpendicular to the screen (that is, superposing the bottom OH with the top one), the same apparent stereochemistry is obtained. (see Fischer projection.)

For a compound with multiple asymmetric carbons, the presence of an internal plane of symmetry indicates that the compound is achiral. However, it is still possible for a compound with multiple asymmetric carbons and no internal plane of symmetry to be meso.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Meso_compound". A list of authors is available in Wikipedia.
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