General Chemistry

First, we need to draw the Lewis structure of IF5.

In short, these are the steps you need to follow for drawing a Lewis structure:

1.  Write the correct skeletal structure for the molecule.

        *   Hydrogen atoms are always terminal (only one bond)

        *   Put more electronegative elements in terminal positions

2. Sum the valence electrons from all the atoms.

3. Use a pair of electrons to form a bond between each pair of bound atoms.

4. Add the remaining electrons to satisfy the octet for a more electronegative atom first.

5. If any atoms lack an octet, make a double or triple bond to give them an octet.

Br is the central atom, so we can draw a preliminary skeletal structure:



There are 5×7 + 7 = 42 electrons, out of which, 10 are used to make 5 covalent bonds. The remaining 30 are divided between the five fluorine atoms, each taking 6 electrons as 3 lone pairs, and Br takes the last pair of electrons:


The hybridization of iodine in IF5 is the same as bromine in BrF5, and we have seen in problem 23 that there are 5 atoms and one lone pair on the central atom, therefore, the electron geometry is octahedral, while the molecular geometry is square pyramidal:

Steric number six indicates sp3d2 hybridization.


Check this 99-question multiple-choice quiz on Geometry and Hybridization:


Geometry and Hybridization Quiz

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