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CHEM 121 Studioby Learn4Less · UBC CHEM 121

CHEM 121 glossary

Molecular geometry

The shape described by the positions of the atoms only; lone pairs affect it but are not part of its name. It equals the electron-domain geometry only when the central atom has no lone pairs.

Central O atom bonded to 2 H atoms, with 2 lone pairs.HOH109.5°Ideal bond angle: 109.5°
Water: the two lone pairs are not "seen" in the shape, which is bent.

Example

XeFX4\ce{XeF4} has an octahedral electron-domain geometry, but with its two lone pairs opposite each other the molecular geometry is square planar.