Lewis structure of ClF₃
28 valence electrons. Three Cl-F single bonds, with two lone pairs on Cl, so Cl has 10 electrons around it (an expanded octet).
Lewis structure
28 valence electronsFormal charges: none
Why this shape
- Cl has 7 valence electrons. It uses three in three single bonds to F, so four are left as two lone pairs.
- Steric number = three sigma bonds + two lone pairs = 5, so Cl is sp³d hybridised.
- Five electron pairs point to the corners of a trigonal bipyramid (trigonal bipyramidal electron geometry). With two lone pairs in place of atoms, the atoms make a T-shaped shape.
- Both lone pairs take equatorial positions, so they are 120 degrees apart and each is 90 degrees from only two bond pairs.
- Both lone pairs sit in the equatorial plane and push the two axial bonds toward the equatorial one, so the angle is about 87.5 degrees, a little less than 90.
- The bond dipoles do not cancel in the T-shaped shape, so ClF₃ is polar.
How to draw it
- Count the valence electrons: Cl 7 + 3 × F 7 = 28 valence electrons, 14 pairs.
- Put Cl in the middle and join it to the three 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: three Cl-F single bonds, with two lone pairs on Cl, so Cl has 10 electrons around it (an expanded octet).
- Formal charge = valence electrons − lone pair electrons − number of bonds. Here: none.
Class 11, Chapter 4 Chemical Bonding and Molecular Structure.
Lewis structure of ClF3: quick answers
How many valence electrons are in ClF3?
Cl 7 + 3 × F 7 = 28 valence electrons, 14 pairs.
What are the formal charges in the Lewis structure of ClF3?
Every atom has a formal charge of zero.
How many lone pairs are in the Lewis structure of ClF3?
11 in all, 2 of them on the central Cl.