Definition

1. Noun:
   • The bivalent radical CH₂ derived from methane: In chemistry, "methylene" refers to a specific chemical group consisting of one carbon atom bonded to two hydrogen atoms, with two remaining bonds available to attach to other atoms or groups. It is a fundamental building block in organic chemistry.

Usage Examples

• Noun:
  • The compound contains a reactive methylene group.
  • Methylene blue is a common dye and medication, though its name refers to a more complex derivative.
  • The chemist discussed the insertion of a methylene bridge between the two aromatic rings.

Advanced Usage

• "Active methylene group": A methylene group (CH₂) that is flanked by two electron-withdrawing groups (like carbonyls), making the hydrogen atoms on it more acidic and reactive.

  • Compounds with an active methylene group are important intermediates in organic synthesis.

• "Methylene bridge" or "Methylene linkage": A -CH₂- unit that connects two other parts of a molecule.

  • The polymer's flexibility is increased by the methylene bridges in its chain.

Variants and Related Words

• Methyl (n): The univalent radical CH₃-, derived from methane.

  • A methyl group is often added or removed in biochemical reactions.

• Methylate (v): To introduce a methyl group into a compound.

  • Scientists methylate the DNA to study gene expression.

• Polymethylene (n): A polymer consisting of repeating methylene units; a term sometimes used for certain types of polyethylene.

  • Polymethylene is a simple hydrocarbon polymer.

Synonyms

• Methylene group: The specific chemical unit.
• Carbene (in a specific context): Refers to the divalent species :CH₂, which is the reactive cousin of the methylene group found in molecules. Note: "Carbene" is a highly reactive intermediate, while "methylene" in a stable compound refers to the -CH₂- unit.

Related Phrases and Terms

• Methylene chloride: Common name for dichloromethane (CH₂Cl₂), an organic solvent.

  • Methylene chloride is often used as a paint stripper.

• Methylene blue: A heterocyclic aromatic compound used as a dye, stain, and medication.

  • The biologist used methylene blue to stain the tissue sample.

Noun

1. the bivalent radical CH2 derived from methane