Is Formaldehyde (CH₂O) Polar or Nonpolar?
Is Formaldehyde (CH₂O) polar or nonpolar?
Formaldehyde has a strongly polar C=O bond (ΔEN = 0.89) and two weakly polar C–H bonds (ΔEN = 0.35). Though the C–H dipoles partially cancel each other, the large C=O dipole dominates, giving a net dipole toward the oxygen.
| Formula | CH₂O |
| Polarity | Polar |
| Molecular Geometry | Trigonal Planar |
| C=O Bond | ΔEN = 0.89 (polar) |
| C–H Bond | ΔEN = 0.35 (weakly polar) |
| Net Dipole | Yes |
Bond Dipoles
The C=O bond has ΔEN = 0.89 - quite polar. The two C–H bonds have ΔEN = 0.35 - only slightly polar. The C=O dipole is the dominant force here.
Molecular Shape & Dipole Cancellation
Formaldehyde is trigonal planar at carbon. The two C–H bonds are symmetric and their small dipoles cancel each other. But the large C=O dipole has no opposing bond to cancel it.
Net Dipole Moment
The net dipole points from carbon toward oxygen, along the C=O bond. This makes formaldehyde a polar molecule. The C=O dipole is responsible for formaldehyde's solubility in water.
See bond dipoles, partial charges, and net dipole moments on interactive 3D molecules.
Visualize Formaldehyde's Polarity in 3DRelated Topics
Lewis Structure of CH₂O
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Formaldehyde VSEPR Shape
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Formaldehyde Intermolecular Forces
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Is Water Polar?
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Is Carbon Dioxide Polar?
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