ClF3 Lewis Structure
Chlorine trifluoride · An extremely reactive fluorinating agent used to clean semiconductor equipment.
The ClF3 Lewis structure has 28 valence electrons, drawn as three Cl–F bonds, with eleven lone pairs in total. The central Cl is sp3d hybridized, which makes it a T-shaped molecule with a bond angle of under 90 degrees. ClF3 is polar: the Cl-F bonds are polar, and the lone pairs on the central atom bend the molecule out of shape, so the dipoles do not cancel.
- 28 valence e−
- T-shaped
- <90° bond angle
- sp3d
- polar
ClF3 molecular geometry
T-shaped, from 5 electron domains on the central Cl: 3 bonded atoms and 2 lone pairs (AX3E2). 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 | 28 |
|---|---|
| Bonding electrons | 6 (3 shared pairs) |
| Nonbonding electrons | 22 (11 lone pairs) |
| Lone pairs on Cl | 2 |
| Electron domains (steric number) | 5 |
| VSEPR notation | AX3E2 |
| Electron geometry | trigonal bipyramidal |
| Molecular geometry | T-shaped |
| Bond angle | <90° |
| Hybridization | sp3d |
| Polarity | polar |
| Formal charges | all zero |
| Resonance structures | none |
| Molar mass | 92.444 g/mol |
Cl Chlorine 7 valence e− F Fluorine 3 atoms, 7 valence e− each
How to draw the ClF3 Lewis structure
Step through it. The bar shows how much of the 28-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. 3 bonds spends 6 electrons.
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Outer octets. Spend electrons as lone pairs on the outer atoms until each has eight. 4 are still unplaced.
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Centre. Everything still unplaced goes on Cl, 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.
7 (Cl) + 3 x 7 (F) = 28 valence electrons -
Choose the central atom
Cl 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.
3 bonds x 2 = 6 electrons used, 22 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 22, 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 Cl, which is in period 3 and can hold more than eight electrons. A period-2 atom could not do this.
10 electrons around Cl -
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.
Cl: 2, F1: 3, F2: 3, F3: 3 (22 electrons) -
Check the central atom
Cl ends up with 10 electrons, an expanded octet. Only period 3 and below can do this.
Cl: 6 bonding + 4 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 Cl: 3 bonded groups plus 2 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 T-shaped arrangement. Both lone pairs go equatorial, leaving three bonds in a T.
steric number 5 -> sp3d -> T-shaped, bond angle under 90 -
Decide whether it is polar
The Cl-F bonds are polar, and the lone pairs on the central atom bend the molecule out of shape, so the dipoles do not cancel.
dipoles do not cancel -> polar
Is ClF3 polar or nonpolar?
ClF3 is polar. The Cl-F bonds are polar, and the lone pairs on the central atom bend the molecule out of shape, so the dipoles do not cancel.
| Bond | Electronegativity difference | Character |
|---|---|---|
| Cl–F | 0.82 | polar covalent |
Common questions
How many valence electrons does ClF3 have?
ClF3 has 28 valence electrons. 6 of them are in bonds and 22 sit in lone pairs.
What is the molecular geometry of ClF3?
ClF3 is a T-shaped molecule. The central Cl has 3 bonded groups and two lone pairs, a steric number of 5, which gives trigonal bipyramidal electron geometry and a T-shaped molecule.
What is the bond angle in ClF3?
The bond angle in ClF3 is under 90 degrees. Both lone pairs go equatorial, leaving three bonds in a T.
What is the hybridization of ClF3?
The central Cl in ClF3 is sp3d hybridized. Steric number 5 means 5 orbitals have to be mixed, which is exactly what sp3d gives you.
Is ClF3 polar or nonpolar?
ClF3 is polar. The Cl-F bonds are polar, and the lone pairs on the central atom bend the molecule out of shape, so the dipoles do not cancel.
Why does ClF3 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.