Definition

Adjective: 1. Not having distinct or opposite poles; not ionic: Describes a molecule or substance that does not have a separation of electric charge, meaning it lacks positive and negative poles. This typically occurs due to an even distribution of electrons within covalent bonds. 2. Lacking polarity; not forming ions in solution: Refers to substances that do not dissociate into charged particles (ions) when dissolved.

Usage and Examples

• Describing molecular structure:
  • Water is a polar molecule, whereas oil is a nonpolar substance.
  • The nonpolar covalent bond means the electrons are shared equally between the atoms.
• Describing solubility and behavior:
  • Nonpolar solvents are often used to dissolve oils and fats.
  • This compound is nonpolar and will not mix with water.

Advanced Usage and Scientific Context

• In chemistry, nonpolar is a fundamental concept contrasting with . It explains the "like dissolves like" rule, where nonpolar solutes dissolve best in nonpolar solvents.
• In biology, nonpolar amino acids are often found in the interior of proteins, away from the aqueous environment.
• The term can describe entire molecules (e.g., methane, CH₄) or specific bonds within a molecule (e.g., the C-H bond).

Variants and Related Words

• Nonpolarity (noun): The state or quality of being nonpolar.
  • The nonpolarity of the lipid bilayer is crucial for cell membrane function.
• Nonionic (adjective): A closely related term often used interchangeably with nonpolar in some contexts, especially regarding surfactants or substances that do not form ions. (As referenced: "a nonionic substance").
  • A nonionic detergent is gentler on fabrics.

Synonyms

• Apolar: A direct synonym, especially used in scientific literature.
• Hydrophobic: While not a perfect synonym, hydrophobic ("water-fearing") substances are typically nonpolar.
• Nonionic: Specifically referring to the lack of ions.

Antonyms

• Polar: Having distinct positive and negative poles.
• Ionic: Relating to, composed of, or using ions.
• Hydrophilic: ("Water-loving"); typically polar.

Adjective

1. not ionic
   • a nonionic substance