Lewis structure of SiCl₄
32 valence electrons. Four Si-Cl single bonds, with no lone pair on Si.
Lewis structure
32 valence electronsFormal charges: none
Why this shape
- Si has 4 valence electrons. It uses four in four single bonds to Cl, so none are left over.
- Steric number = four sigma bonds + no lone pairs = 4, so Si is sp³ hybridised.
- Four electron pairs point to the corners of a tetrahedron (tetrahedral electron geometry). With no lone pairs the atoms take the same shape: tetrahedral.
- All the bond pairs repel each other equally, so the angle is the ideal 109.5°.
- The bond dipoles cancel in the symmetric tetrahedral shape, so SiCl₄ is non-polar.
How to draw it
- Count the valence electrons: Si 4 + 4 × Cl 7 = 32 valence electrons, 16 pairs.
- Put Si in the middle and join it to the four outer atoms with single bonds.
- Give each outer atom lone pairs until it has an octet (H needs only two electrons), then put any electrons left over on the central atom.
- Result: four Si-Cl single bonds, with no lone pair on Si.
- Formal charge = valence electrons − lone pair electrons − number of bonds. Here: none.
Class 11, Chapter 4 Chemical Bonding and Molecular Structure.
Lewis structure of SiCl4: quick answers
How many valence electrons are in SiCl4?
Si 4 + 4 × Cl 7 = 32 valence electrons, 16 pairs.
What are the formal charges in the Lewis structure of SiCl4?
Every atom has a formal charge of zero.
How many lone pairs are in the Lewis structure of SiCl4?
12 in all, none on the central Si.