Methyleen

Methyleen is the Dutch term for the methylene group, a divalent carbon fragment with the formula -CH2-. It arises from methane by removal of two hydrogen atoms and functions as a linking unit in many organic molecules. As a substituent, a methylene group can connect two moieties (a methylene bridge) or be part of a saturated carbon chain.

The methylene group is typically sp3-hybridized and is found in alkanes as well as in many natural and synthetic compounds where it links rings or functional groups. For example, in diphenylmethane the central CH2 links two phenyl rings. In polymers, repeating -CH2- units form polymethylene segments that can vary in length.

The term is used across chemistry, biochemistry, and materials science. It is distinct from related terms such as methyl (CH3), methine (CH), and methylidene (the =CH2 group in certain contexts). The exact meaning can depend on whether the -CH2- is a bridging fragment or part of a continuous carbon skeleton.

In Dutch chemical literature, methyleen is a standard name for this fragment. It is a fundamental concept for understanding hydrocarbon structure, reactivity in methylenation-type reactions, and the design of polymers and natural products.

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