Methylene bridge

In chemistry, a methylene bridge is part of a molecule with formula −CH2. The carbon atom is connected by single bonds to two other distinct atoms in the rest of the molecule. A methylene bridge is often called a methylene group or simply methylene, as in "methylene chloride" (dichloromethane CH
2
Cl
2
). As a bridge in other compounds, for example in cyclic compounds, it is given the name methano. However, the term methylidene group (not to be confused with the term methylene group, nor the carbene methylidene) properly applies to the CH
2
group when it is connected to the rest of the molecule by a double bond (=CH2), giving it chemical properties very distinct from those of a bridging CH
2
group.