MOLECULAR POLARITYFIELD NOTE 163 / 175
Is SiH4 polar or nonpolar?
SiH4 is a nonpolar molecule because its perfect tetrahedral symmetry causes all four Si–H bond dipoles to cancel completely.
Silane · tetrahedral
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 SiH4 is nonpolar
Silane is the silicon analog of methane. Hydrogen (2.20) is slightly more electronegative than silicon (1.90), so each Si–H bond is weakly polar with the positive end on silicon.
What to notice
Each Si–H bond has a slight dipole, but all four hydrogens occupy equivalent positions around silicon. The molecular dipole sums to zero.
Common questions about SiH4
- 01
What does the Lewis structure of SiH4 show?
Si forms four single Si–H bonds and has no lone pair.
- 02
What is the molecular geometry of SiH4?
SiH4 has a tetrahedral molecular geometry. The 3D model shows representative bond angles of 109.5°. These angles come from the displayed model coordinates.
- 03
What is the molar mass of SiH4?
SiH4 has an approximate molar mass of 32.12 g/mol, calculated from its formula using abridged standard atomic weights. Natural isotope variation can change the last digits.