Difluorocarbene (CF₂) Lewis structure
18 valence electrons, bent
Build CF₂ step by step in the Lewis Structure Generator
What is the Lewis structure of CF₂?
Difluorocarbene, CF₂, has 18 valence electrons. Carbon is the central atom, joined by two C−F single bonds. It carries one lone pair on the central C and three on each F. Every formal charge is zero. C is AX₂E₁: bent, with an ideal bond angle of 120°, and the molecule is polar.
Valence electrons in CF₂
In one line: 4 + 2 × 7 = 18. Each atom brings the valence electrons its group gives it.
How to draw the CF₂ Lewis structure
- Count the valence electrons. Valence electrons: C 4 and each F 7. 4 + 2 × 7 = 18.
- Choose the central atom. C goes in the middle: C is the least electronegative atom other than H, χ 2.55 against 3.98 for F.
- Join the atoms with single bonds. Two single bonds use 4 electrons, leaving 18 − 4 = 14.
- Complete the outer atoms. Each outer atom takes enough lone pairs to reach eight: 2 F × 6 = 12, leaving 14 − 12 = 2.
- Put the rest on the central atom. The 2 left go on the central atom as one lone pair on C, and C now has 6 electrons round it.
- Make multiple bonds where needed. C is left with 6 electrons. A double bond from an outer atom would complete its octet only by putting positive charge on the more electronegative atom, so C stays short, one of the known exceptions to the octet rule.
Lone pairs and formal charges in CF₂
| Atom | Number | Bonds | Lone pairs | Electrons round it | Formal charge, V − N − B/2 |
|---|---|---|---|---|---|
| C (central) | 1 | two single bonds | 1 | 6 | 4 − 2 − 2 = 0 |
| F | 2 | one single bond | 3 | 8 | 7 − 6 − 1 = 0 |
V is the atom’s valence electrons, N its nonbonding electrons and B its bonding electrons. The formal charges add up to 0, the molecule’s overall charge.
Shape and polarity of CF₂
| Central atom | C |
|---|---|
| VSEPR class | AX₂E₁ |
| Electron geometry | trigonal planar |
| Molecular geometry | bent |
| Ideal bond angle | 120° |
| Polarity, an estimate | polar |
The bent shape leaves the bond dipoles unbalanced.
C has two σ bonds and one lone pair, three electron domains in all, so its electron geometry is trigonal planar. Counting only the bonded atoms, the molecular geometry is bent.
The VSEPR Molecular Geometry viewer turns the AX₂E₁ shape in 3D, lone pairs included.
Notes on the CF₂ Lewis structure
- Carbon has only six electrons here, two bonds and a lone pair, which makes CF₂ a carbene, a reactive intermediate.
Work with CF₂
- Lewis Structure Generator: CF₂ built step by step, with every formal charge worked out
- VSEPR Molecular Geometry: every VSEPR shape in 3D, with its bond angles
- All 78 Lewis structures: valence electrons, resonance, shape and polarity in one table