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Polar Molecule

Polar molecule: net μ ≠ 0; e.g., H₂O (μ = 1.85 D), NH₃ (1.47 D)
Quick Reference
Formula / NotationPolar molecule: net μ ≠ 0; e.g., H₂O (μ = 1.85 D), NH₃ (1.47 D)
Also Known AsPolar molecule, dipolar molecule, net dipole molecule

What is Polar Molecule?

A molecule with a net dipole moment resulting from the vector sum of bond dipoles. A molecule can have polar bonds but be nonpolar if the bond dipoles cancel due to molecular symmetry. Water is polar; carbon dioxide is nonpolar despite having polar C=O bonds.

Formula & Notation

Polar molecule: net μ ≠ 0; e.g., H₂O (μ = 1.85 D), NH₃ (1.47 D)

Other Names / Synonyms: Polar molecule, dipolar molecule, net dipole molecule

Properties & Characteristics

A polar molecule has a non-zero dipole moment (μ ≠ 0) due to an asymmetric distribution of electron density. This arises when: (1) the molecule contains polar bonds AND (2) the molecular geometry does not allow the bond dipoles to cancel. Examples: H₂O (bent, μ = 1.85 D), NH₃ (pyramidal, μ = 1.47 D), HCl (linear, μ = 1.08 D). Non-examples: CO₂ (linear, dipoles cancel), CCl₄ (tetrahedral, dipoles cancel).

Uses & Applications

Polar molecules dissolve in polar solvents (water, alcohols), exhibit strong intermolecular forces (dipole-dipole, hydrogen bonds), have higher boiling points than comparable nonpolar molecules, and undergo specific interactions with biological macromolecules. The polarity of drug molecules determines their pharmacokinetics (absorption, distribution, metabolism, excretion — ADME).

Safety Information

Polar molecules generally have higher water solubility, which can increase both bioavailability (for drugs) and environmental mobility (for pollutants). DMSO and other polar aprotic solvents can carry dissolved toxic compounds through skin. Understanding molecular polarity is essential for predicting exposure routes and biological effects.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Polar Molecule
Formula Polar molecule: net μ ≠ 0; e.g., H₂O (μ = 1.85 D), NH₃ (1.47 D)
Synonyms Polar molecule, dipolar molecule, net dipole molecule

Frequently Asked Questions

A molecule with a net dipole moment resulting from the vector sum of bond dipoles. A molecule can have polar bonds but be nonpolar if the bond dipoles cancel due to molecular symmetry. Water is polar; carbon dioxide is nonpolar despite having polar C=O bonds.

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