Definition

1. Noun:
   • A specific type of intermolecular attraction: A hydrogen bond is a relatively weak chemical bond. It forms when a hydrogen atom that is covalently bonded to one electronegative atom (like oxygen or nitrogen) is also attracted to another nearby electronegative atom. This attraction is crucial for the structure and properties of many substances.

Usage

• Hydrogen bonds are intermolecular forces, meaning they occur molecules, not within a single molecule (with some exceptions in large molecules like proteins or DNA).
• They are essential in determining the physical properties of substances, such as the high boiling point of water.
• They play a critical role in the three-dimensional structure of biological molecules like proteins and nucleic acids (DNA/RNA).

Examples

• Noun:
  • The unique properties of water are largely due to the presence of hydrogen bonds between its molecules.
  • In DNA, hydrogen bonds hold the two strands of the double helix together by connecting the nitrogenous bases.

Advanced Usage

• "To form a hydrogen bond": describes the specific action of this bond being created.
  • The alcohol molecule can form a hydrogen bond with water.
• "Hydrogen-bonded" (adjective): describes a structure or state held together by these bonds.
  • The hydrogen-bonded network in ice gives it a less dense structure than liquid water.

Variants and Related Words

• Hydrogen bonding (n): The general phenomenon or the collective action of hydrogen bonds.
  • Hydrogen bonding is a key concept in organic chemistry.
• H-bond (n): A common abbreviation for "hydrogen bond."
  • The strength of an H-bond is less than that of a covalent bond.

Synonyms

• Intermolecular attraction: A broader term for forces between molecules, which includes hydrogen bonding.
• Non-covalent interaction: A general term for chemical bonds that do not involve sharing electrons, encompassing hydrogen bonds, ionic interactions, and van der Waals forces.

Related Phrases

• Donor and acceptor: In a hydrogen bond, the atom to which the hydrogen is covalently bonded is the donor. The other electronegative atom that attracts the hydrogen is the acceptor.
  • In a water dimer, one oxygen acts as a hydrogen bond donor and the other as an acceptor.

Key Concepts

• Strength: A hydrogen bond is stronger than other van der Waals forces but significantly weaker than a covalent or ionic bond.
• Directionality: Hydrogen bonds have a preferred orientation, which influences the shape of molecules and crystals.
• Biological Significance: Hydrogen bonds are fundamental to the function of enzymes, the stability of DNA, and the folding of proteins.

Noun

1. a chemical bond consisting of a hydrogen atom between two electronegative atoms (e.g., oxygen or nitrogen) with one side be a covalent bond and the other being an ionic bond