Iodine heptafluoride (IF₇) Lewis structure
56 valence electrons, pentagonal bipyramidal
Build IF₇ step by step in the Lewis Structure Generator
What is the Lewis structure of IF₇?
Iodine heptafluoride, IF₇, has 56 valence electrons. Iodine is the central atom, joined by seven I−F single bonds. It carries three lone pairs on each F. Every formal charge is zero. I is AX₇: pentagonal bipyramidal, and the molecule is nonpolar.
Valence electrons in IF₇
In one line: 7 + 7 × 7 = 56. Each atom brings the valence electrons its group gives it.
How to draw the IF₇ Lewis structure
- Count the valence electrons. Valence electrons: I 7 and each F 7. 7 + 7 × 7 = 56.
- Choose the central atom. I goes in the middle: I is the least electronegative atom other than H, χ 2.66 against 3.98 for F.
- Join the atoms with single bonds. Seven single bonds use 14 electrons, leaving 56 − 14 = 42.
- Complete the outer atoms. Each outer atom takes enough lone pairs to reach eight: 7 F × 6 = 42, leaving 42 − 42 = 0.
- Put the rest on the central atom. Nothing is left, so I gets no lone pair, and I now has 14 electrons round it. That is more than eight, which an atom from period 3 on can hold.
- Make multiple bonds where needed. Every atom already has an octet or more, so no lone pair needs to become a bond.
Lone pairs and formal charges in IF₇
| Atom | Number | Bonds | Lone pairs | Electrons round it | Formal charge, V − N − B/2 |
|---|---|---|---|---|---|
| I (central) | 1 | seven single bonds | 0 | 14 | 7 − 0 − 7 = 0 |
| F | 7 | 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 IF₇
| Central atom | I |
|---|---|
| VSEPR class | AX₇ |
| Electron geometry | pentagonal bipyramidal |
| Molecular geometry | pentagonal bipyramidal |
| Ideal bond angle | not given for seven domains |
| Polarity, an estimate | nonpolar |
Seven identical bonds in a pentagonal bipyramid cancel exactly.
I has seven σ bonds and no lone pairs, seven electron domains in all, so its electron geometry is pentagonal bipyramidal. With no lone pairs, the molecular geometry is the same.
Notes on the IF₇ Lewis structure
- I has seven electron domains, AX₇: pentagonal bipyramidal. The VSEPR viewer stops at six, so it has no 3D model of this shape.
Work with IF₇
- Lewis Structure Generator: IF₇ 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