What is the difference between bulk, cluster, and molecule in material science?

[assed]

I often find those terms when dealing with material science but I can't teel precisely the difference or the definition of which of these terms. Can anyone help me?

 

[nasu]

Have you tried to look them up?
The meanings are quite different so should be little ground for confusion.

For me it's not clear what your problem is actually.
You read about material science and are confused about "molecule"?

 

[assed]

Well...your answer was not helpfull at all. Of course I tried to look them up before asking here. I never said I was confused about molecules, what I meant is that I cannot precisely determine what tells the diference between a cluster and a molecule. Besides that what i understand when I hear bulk is that we're talking about the internal part of the compound, not dealing with surface. Well, now that I explained myself better maybe someone could see what my problem is and help me.

 

[nasu]

Your explanation was helpful though.

In my understanding, a cluster is an aggregate of atoms or molecules so that the properties are somehow between these of the single molecules and those of a macroscopic solid (bulk).
But I suppose you know this already.

A similar problem is maybe defining what makes a particle a "nanoparticle".
They have some "special" properties. For example superficial phenomena becomes important. Or magnetic nano particles do not break into domains like bulk ferromagnets.
The specific size may depend on the material and the properties under study.

So clusters may be made from a few atoms up to thousands, maybe more.