XeF2 Lewis Structure
Xenon difluoride · One of the few stable compounds of a noble gas, used to fluorinate other molecules.
The XeF2 Lewis structure has 22 valence electrons, drawn as two Xe–F bonds, with nine lone pairs in total. The central Xe is sp3d hybridized and the molecule is linear, with a bond angle of 180 degrees. XeF2 is nonpolar: the bond dipoles and lone pairs are arranged symmetrically, so the vectors cancel and the molecule has no net dipole.
- 22 valence e−
- linear
- 180° bond angle
- sp3d
- nonpolar
XeF2 molecular geometry
Linear, from 5 electron domains on the central Xe: 2 bonded atoms and 3 lone pairs (AX2E3). The electron geometry is trigonal bipyramidal; the shape is what is left when the lone pairs are not counted as atoms. Wedges point toward you, hashed wedges away. Every shape in the VSEPR chart →
Calculated properties
| Total valence electrons | 22 |
|---|---|
| Bonding electrons | 4 (2 shared pairs) |
| Nonbonding electrons | 18 (9 lone pairs) |
| Lone pairs on Xe | 3 |
| Electron domains (steric number) | 5 |
| VSEPR notation | AX2E3 |
| Electron geometry | trigonal bipyramidal |
| Molecular geometry | linear |
| Bond angle | 180° |
| Hybridization | sp3d |
| Polarity | nonpolar |
| Formal charges | all zero |
| Resonance structures | none |
| Molar mass | 169.286 g/mol |
Xe Xenon 8 valence e− F Fluorine 2 atoms, 7 valence e− each
How to draw the XeF2 Lewis structure
Step through it. The bar shows how much of the 22-electron budget is spent at each stage - it never grows, which is the whole constraint.
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Skeleton. Join every connected pair with one bond. 2 bonds spends 4 electrons.
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Outer octets. Spend electrons as lone pairs on the outer atoms until each has eight. 6 are still unplaced.
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Centre. Everything still unplaced goes on Xe, which now has 10 electrons around it.
The reasoning at each step
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Count the valence electrons
Add up the outer-shell electrons every atom brings. That total is the budget for the whole structure - every line and every dot has to come out of it, and nothing may be added.
8 (Xe) + 2 x 7 (F) = 22 valence electrons -
Choose the central atom
Xe is the least electronegative atom here, so it takes the centre. Hydrogen is never central: it can only form one bond.
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Join everything with single bonds first
Every connection starts as one shared pair. Draw them all before worrying about double bonds - the arithmetic in the next step is what tells you where the double bonds have to go.
2 bonds x 2 = 4 electrons used, 18 left -
Work out how far short you are
Add up what every atom still needs to fill its shell - eight electrons for most atoms, two for hydrogen - minus what its single bonds already give it. Compare that with the electrons you have left. The difference decides everything that follows.
needs 16, has 18, 2 to spare -
Park the spare electrons on the central atom
There are 2 electrons more than the outer atoms can use. They become 1 extra lone pair on Xe, which is in period 5 and can hold more than eight electrons. A period-2 atom could not do this.
10 electrons around Xe -
Fill in the lone pairs
Every electron not in a bond sits as a lone pair on an atom. Each atom takes exactly what it needs to finish its shell - there is no choice left at this point.
Xe: 3, F1: 3, F2: 3 (18 electrons) -
Check the central atom
Xe ends up with 10 electrons, an expanded octet. Only period 3 and below can do this.
Xe: 4 bonding + 6 nonbonding = 10 -
Check the formal charges
Formal charge is valence electrons, minus lone-pair electrons, minus the number of bonds. Every atom here comes out at zero, which is the sign of a good structure.
all formal charges = 0 -
Work out the shape
Count the electron domains on Xe: 2 bonded groups plus 3 lone pairs. A double or triple bond still counts as one domain, because it points in one direction. That gives trigonal bipyramidal electron geometry; ignore the lone pairs and the atoms themselves sit in a linear arrangement. Three equatorial lone pairs leave the two bonds opposite each other.
steric number 5 -> sp3d -> linear, bond angle 180 -
Decide whether it is polar
The bond dipoles and lone pairs are arranged symmetrically, so the vectors cancel and the molecule has no net dipole.
dipoles cancel -> nonpolar
Is XeF2 polar or nonpolar?
XeF2 is nonpolar. The bond dipoles and lone pairs are arranged symmetrically, so the vectors cancel and the molecule has no net dipole.
| Bond | Electronegativity difference | Character |
|---|---|---|
| Xe–F | 1.38 | polar covalent |
Common questions
How many valence electrons does XeF2 have?
XeF2 has 22 valence electrons. 4 of them are in bonds and 18 sit in lone pairs.
What is the molecular geometry of XeF2?
XeF2 is a linear molecule. The central Xe has 2 bonded groups and three lone pairs, a steric number of 5, which gives trigonal bipyramidal electron geometry and a linear molecule.
What is the bond angle in XeF2?
The bond angle in XeF2 is 180 degrees. Three equatorial lone pairs leave the two bonds opposite each other.
What is the hybridization of XeF2?
The central Xe in XeF2 is sp3d hybridized. Steric number 5 means 5 orbitals have to be mixed, which is exactly what sp3d gives you.
Is XeF2 polar or nonpolar?
XeF2 is nonpolar. The bond dipoles and lone pairs are arranged symmetrically, so the vectors cancel and the molecule has no net dipole.
Why does XeF2 break the octet rule?
The central atom has more than four bonded groups, so it has to hold more than eight electrons. Elements from period 3 downward can do this; period-2 elements like carbon, nitrogen and oxygen cannot.