Molecular Geometry of Formaldehyde (CH₂O) - VSEPR Theory

What is the molecular geometry of Formaldehyde (CH₂O)?

Formaldehyde (CH₂O) has 3 electron domains around the central C atom: 3 bonding and 0 lone pair(s). The electron domain geometry is trigonal planar, giving a trigonal planar molecular shape with bond angles of approximately 120 degrees.

FormulaCH₂O
NameFormaldehyde
Central AtomC
Bonding Domains3
Lone Pair Domains0
Total Electron Domains3
Electron Domain GeometryTrigonal Planar
Molecular GeometryTrigonal Planar
Bond Angle120°

Electron Domain Count

Carbon has 3 bonding domains: one C=O double bond (counts as 1 domain) and two C–H single bonds. No lone pairs = 3 total domains.

Electron Domain Geometry

3 electron domains arrange in a trigonal planar pattern (120° apart). All atoms lie in the same plane.

Molecular Geometry

All 3 domains are bonding pairs, so the molecular geometry matches: trigonal planar. The molecule is flat.

Bond Angle

The ideal bond angle is 120°. In reality, the C=O double bond occupies slightly more space, compressing the H–C–H angle slightly below 120°.

See electron domains, molecular shapes, and bond angles on interactive 3D molecules with Lewis structure overlays.

Visualize Formaldehyde's Geometry in 3D

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