MOLECULAR POLARITYFIELD NOTE 167 / 175
Is SO3 polar or nonpolar?
SO3 is a nonpolar molecule because its trigonal planar shape causes the three polar S=O bond dipoles to cancel symmetrically.
Sulfur Trioxide · trigonal planar
The molecule in space
Drag to turn the molecule. Show angles to read the model geometry.
01 / MODEL RECORDPubChem 3D coordinates. Atom sizes and bond thickness are illustrative.How model data is used ↗
Why SO3 is nonpolar
Sulfur trioxide has a trigonal planar structure with 120° bond angles and no lone pairs on sulfur.
What to notice
SO3 and SO2 contain polar S–O bonds, but their overall shapes differ. Three equal directions in a plane cancel in SO3.
Common questions about SO3
- 01
What does the Lewis structure of SO3 show?
An expanded-octet Lewis sketch draws three S=O double bonds around S. Resonance and delocalization are more informative than treating one fixed drawing as unique.
- 02
What is the molecular geometry of SO3?
SO3 has a trigonal planar molecular geometry. The 3D model shows representative bond angles of 120°. These angles come from the displayed model coordinates.
- 03
What is the molar mass of SO3?
SO3 has an approximate molar mass of 80.06 g/mol, calculated from its formula using abridged standard atomic weights. Natural isotope variation can change the last digits.