XeO3 Lewis Structure
Xenon trioxide · An unstable, explosive oxide of xenon.
The XeO3 Lewis structure has 26 valence electrons, drawn as three Xe–O bonds, with ten lone pairs in total. The central Xe is sp3 hybridized, which makes it a trigonal pyramidal molecule with a bond angle of 107 degrees. XeO3 is polar: the Xe-O bonds are polar, and the lone pair on the central atom bends the molecule out of shape, so the dipoles do not cancel.
- 26 valence e−
- trigonal pyramidal
- ≈107° bond angle
- sp3
- polar
XeO3 molecular geometry
Trigonal pyramidal, from 4 electron domains on the central Xe: 3 bonded atoms and 1 lone pair (AX3E1). The electron geometry is tetrahedral; 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 | 26 |
|---|---|
| Bonding electrons | 6 (3 shared pairs) |
| Nonbonding electrons | 20 (10 lone pairs) |
| Lone pairs on Xe | 1 |
| Electron domains (steric number) | 4 |
| VSEPR notation | AX3E1 |
| Electron geometry | tetrahedral |
| Molecular geometry | trigonal pyramidal |
| Bond angle | ≈107° |
| Hybridization | sp3 |
| Polarity | polar |
| Formal charges | Xe: +3, O: -1, O: -1, O: -1 |
| Resonance structures | none |
| Molar mass | 179.287 g/mol |
Xe Xenon 8 valence e− O Oxygen 3 atoms, 6 valence e− each
How to draw the XeO3 Lewis structure
Step through it. The bar shows how much of the 26-electron budget is spent at each stage - it never grows, which is the whole constraint.
-
Skeleton. Join every connected pair with one bond. 3 bonds spends 6 electrons.
-
Outer octets. Spend electrons as lone pairs on the outer atoms until each has eight. 2 are still unplaced.
-
Centre. Everything still unplaced goes on Xe, which now has 8 electrons around it.
The reasoning at each step
-
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) + 3 x 6 (O) = 26 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.
-
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.
3 bonds x 2 = 6 electrons used, 20 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 20, has 20, exactly enough -
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: 1, O1: 3, O2: 3, O3: 3 (20 electrons) -
Check the central atom
Xe ends up with a full octet. Every electron in the budget is now placed.
Xe: 6 bonding + 2 nonbonding = 8 -
Check the formal charges
Formal charge is valence electrons, minus lone-pair electrons, minus the number of bonds. They are not real charges, but they have to add up to zero on a neutral molecule, and a structure that keeps them small is the better one.
Xe: 8 - 2 - 3 = +3 ; O1: 6 - 6 - 1 = -1 ; O2: 6 - 6 - 1 = -1 ; O3: 6 - 6 - 1 = -1 -
Work out the shape
Count the electron domains on Xe: 3 bonded groups plus 1 lone pair. A double or triple bond still counts as one domain, because it points in one direction. That gives tetrahedral electron geometry; ignore the lone pairs and the atoms themselves sit in a trigonal pyramidal arrangement. One lone pair pushes the three bonds down from the ideal 109.5 degrees.
steric number 4 -> sp3 -> trigonal pyramidal, bond angle 107 -
Decide whether it is polar
The Xe-O bonds are polar, and the lone pair on the central atom bends the molecule out of shape, so the dipoles do not cancel.
dipoles do not cancel -> polar
The expanded-octet version
Courses disagree about XeO3. The structure at the top of this page obeys the octet rule and leaves formal charges behind. The one below puts more than eight electrons on the central atom and brings every formal charge to zero. Check which convention your course uses.
Is XeO3 polar or nonpolar?
XeO3 is polar. The Xe-O bonds are polar, and the lone pair on the central atom bends the molecule out of shape, so the dipoles do not cancel.
| Bond | Electronegativity difference | Character |
|---|---|---|
| Xe–O | 0.84 | polar covalent |
Common questions
How many valence electrons does XeO3 have?
XeO3 has 26 valence electrons. 6 of them are in bonds and 20 sit in lone pairs.
What is the molecular geometry of XeO3?
XeO3 is a trigonal pyramidal molecule. The central Xe has 3 bonded groups and one lone pair, a steric number of 4, which gives tetrahedral electron geometry and a trigonal pyramidal molecule.
What is the bond angle in XeO3?
The bond angle in XeO3 is 107 degrees. One lone pair pushes the three bonds down from the ideal 109.5 degrees.
What is the hybridization of XeO3?
The central Xe in XeO3 is sp3 hybridized. Steric number 4 means 4 orbitals have to be mixed, which is exactly what sp3 gives you.
Is XeO3 polar or nonpolar?
XeO3 is polar. The Xe-O bonds are polar, and the lone pair on the central atom bends the molecule out of shape, so the dipoles do not cancel.
Does XeO3 obey the octet rule?
It can be drawn either way, and different courses teach different conventions. The octet structure keeps eight electrons on every atom but leaves formal charges behind. The expanded-octet structure puts more than eight electrons on the central atom and brings every formal charge to zero. Both are shown on this page.