Question

Based on the VSPER theory, what is the molecular geometry of a molecule of $P{I}_3$ ?

Answer 1

VSPER Theory allows for the prediction of molecular shapes based on the number of electron pairs that surround their respective atoms.

In order to determine the molecular shape of the $P{I}_3$ molecule using VSPER Theory, its Lewis structure must first be determined.

Since $P$ has $5$ valence electrons, and each $I$ atom has $7$ valence electrons, the molecule's Lewis structure wil look like this:(refer to image)

Notice that P uses $3$ valence electrons to form covalent bonds with the three $I$ atoms, which leaves it with one lone pair of electrons.

P has a steric number of $4$ and a coordination number of $3,$ which means that it has a tetrahedral electron geometry and a trigonal planar molecular geometry:

Here's a representation of $P{I}_3$'s molecular geometry