Is Phosphine (PH₃) Polar or Nonpolar?
Is Phosphine (PH₃) polar or nonpolar?
PH₃ has nearly nonpolar P–H bonds (ΔEN ≈ 0.01), yet the molecule is slightly polar. The lone pair on phosphorus creates an asymmetric electron distribution, giving a small net dipole.
| Formula | PH₃ |
| Polarity | Polar |
| Molecular Geometry | Trigonal Pyramidal |
| P–H Bond | ΔEN = 0.01 (weakly polar) |
| Net Dipole | Yes |
Bond Dipoles
Each P–H bond has a tiny ΔEN of 0.01 (P = 2.19, H = 2.20) - essentially nonpolar bonds. But polarity is not determined by bond dipoles alone.
Molecular Shape & Dipole Cancellation
PH₃ is trigonal pyramidal (93.3°), like ammonia but with narrower angles. The lone pair on phosphorus creates an asymmetric electron distribution.
Net Dipole Moment
Despite nearly nonpolar bonds, the lone pair on phosphorus creates a small net dipole pointing away from the lone pair. PH₃ is weakly polar (0.58 D vs ammonia's 1.47 D).
See bond dipoles, partial charges, and net dipole moments on interactive 3D molecules.
Visualize Phosphine's Polarity in 3DRelated Topics
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