# Why Does IF5 Exhibit a Square Pyramidal Shape Despite Exceeding the Octet Rule?

• Chemistry
• jolly_math
In summary, the molecular structure of IF5 is trigonal bipyramidal with a central iodine atom bonded to five fluorine atoms in a symmetrical arrangement. It has five bonding electron pairs and one non-bonding electron pair, resulting in a total of six electron pairs around the central iodine atom. The bond angle in IF5 is approximately 90 degrees between the axial fluorine atoms and 120 degrees between the equatorial fluorine atoms. This molecular structure allows IF5 to have high reactivity and strong oxidizing properties, as well as making it a polar molecule with the ability to undergo dipole-dipole interactions. The Lewis structure for IF5 consists of an iodine atom bonded to five fluorine atoms,
jolly_math
Homework Statement
Predict the molecular structure of IF5 and its overall polarity.
Relevant Equations
lewis structure
VSEPR
I thought it was trigonal bipyramidal, with iodine forming 5 bonds with 5 fluorine atoms. Actually, iodine has another lone electron pair, making it square planar.

Is there a reason why iodine has another lone pair when it has already exceeded the octet rule? And how would I predict how many electron pairs a central atom exceeding the octet rule would have? Thank you.

Iodine has 7 valence electrons. The fluorines contribute 1 each. So you have 12 electrons, or 6 pairs to arrange around the I atom.
And IF5 is square pyramidal, not square planar.

jolly_math

## 1. What is the molecular formula for IF5?

The molecular formula for IF5 is IF5. This means that the molecule is composed of one atom of iodine and five atoms of fluorine.

## 2. What is the Lewis structure for IF5?

The Lewis structure for IF5 is a trigonal bipyramidal shape, with the central iodine atom bonded to five fluorine atoms. The lone pairs of electrons on the central atom are represented by two dots above the iodine symbol.

## 3. What is the bond angle in IF5?

The bond angle in IF5 is 90 degrees between the axial fluorine atoms and 120 degrees between the equatorial fluorine atoms. This is due to the repulsion between the bonded and lone pairs of electrons on the central atom.

## 4. Is IF5 polar or nonpolar?

IF5 is a polar molecule due to the unequal distribution of electrons between the iodine and fluorine atoms. The fluorine atoms are more electronegative, causing a partial negative charge, while the iodine atom has a partial positive charge.

## 5. What are the uses of IF5?

IF5 is mainly used as a fluorinating agent in organic synthesis, as it can replace hydrogen atoms with fluorine atoms in molecules. It is also used in the production of other fluorine compounds and in the semiconductor industry as an etching agent.

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