Covalent molecules are usually held in a crystal structure by

Which substance has the strongest London dispersion forces?

In solid argon,the atoms are held together by

What is the dependence of interaction energy on the distance $(r)$ between molecules for the following forces?
$(i)$ London forces
$(ii)$ Dipole-dipole forces (stationary)
$(iii)$ Dipole-induced dipole forces

Solid $PCl_5$ exists as $:$

Solid $PCl_5$ exists as