What happens when `"PCl"_(5)` is heated ?

Explanation

In `"PCl"_(3)`, there are 5P-Cl bonds, out of which three are equatorial (longer) and two are axial (shorter). When `"PCl"_(5)` is heated strongly, two less stable axial bonds break andd phosphorus trichloride `("PCl"_(3))` is formed.
`underset("Pentachloride")underset("Phosphorus")(PCl_(5))overset("Strong heating")tounderset("trichloride")underset("Phosphorus")(PCl_(3))+Cl_(2)`
If `PCl_(5)` is warmed slightly, it sublimes only without decomposing.

Structure of `PCl_(5)` showing axial and equatorial bonds.