"Diffusion in solids rather than of solids is more common" explain.
Dear student,
The statement means that there cannot be any diffusion of solid substance because the atoms are bonded tightly with each other and so cannot move so there is no diffusion of solid substance but solid although have less intermolecular space between them but liquid and air can diffuse through them so diffusion can happen in/through solids but solid substances cannot diffuse themselves.
example : a brick on its own cannot move/ cannot diffuse but water can diffuse through it.
Regards
The statement means that there cannot be any diffusion of solid substance because the atoms are bonded tightly with each other and so cannot move so there is no diffusion of solid substance but solid although have less intermolecular space between them but liquid and air can diffuse through them so diffusion can happen in/through solids but solid substances cannot diffuse themselves.
example : a brick on its own cannot move/ cannot diffuse but water can diffuse through it.
Regards