Molecular geometry

Molecular geometry is the three-dimensional arrangement of atoms in a molecule. It is shaped by bonding, electron-pair repulsions, and the molecule’s environment.

Valence-shell electron-pair repulsion theory: A model that predicts molecular shapes from repulsions among electron pairs around a central atom. It predicts many molecular geometries by placing electron domains as far apart as possible.
Chemical bond: An attraction that holds atoms or ions together in a chemical substance. Bond connectivity sets which atoms are positioned relative to one another.
Dipole moment: A vector measure of the separation of positive and negative charge in a system. A molecule’s shape determines how its bond dipoles combine into an overall dipole.
Molecular topology: The pattern of atomic connectivity in a molecule, independent of its exact spatial dimensions. Topology specifies which atoms connect; geometry specifies their three-dimensional arrangement.
Molecular orbital theory: A theory that describes electrons in molecules as occupying orbitals spread across multiple atoms. Its delocalized orbitals explain bonding and shapes that localized bond pictures cannot fully capture.
Bond angle: The angle between two bonds that share an atom. Bond angles are measurable quantities that distinguish one molecular shape from another.
Vibrational spectroscopy: The study of molecular vibrations through their interaction with electromagnetic radiation. Vibrational spectra reveal structural details such as bond strengths and molecular symmetry.
Molecular configuration: A fixed spatial arrangement of atoms that cannot change without breaking or reforming bonds. Configuration distinguishes stereochemical arrangements from geometry changes caused by bond rotation.
Hybrid orbital: An orbital formed by combining atomic orbitals on the same atom into new directional orbitals. Hybrid orbitals offer a bonding picture that connects orbital direction with molecular shape.
Bond length: The distance between the nuclei of two bonded atoms. Molecular geometry includes interatomic distances as well as angles and orientation.

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