In solid-state, PCl5 exists as:
1. Covalent solid.
2. Octahedral structure.
3. Ionic solid with PCl6+ octahedral and PCl4- tetrahedral.
4. Ionic solid with PCl4+ tetrahedral and PCl6- octahedral.

HINT: PCl5 generates ions in solid form.
Explanation:
STEP 1: In solid state PCl5 exists as an ionic solid with PCl4+ tetrahedral and PCl6- octahedral.
In solid state, PCl5 prefer to exist as oppositely charged ions like PCl4+ and PCl6-as the ionic bonding enhances the crystalline nature .
STEP 2: The attractive forces in an ionic crystal are much greater than the dipole-dipole or dispersion in crystals of covalent substances.