Connection between spherical packing and lattices?

[mahela007]

What is the connection between spherical packing and lattice structures of atoms or molecule? For example, i can't see any relationship between spherical packing and the structure of graphite..

 

[Borek]

Good, structure of graphite is not related to spherical packing. However, take a look at structures of metals.

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[mahela007]

So when can spherical packing be "applied" to a lattice?

 

[Borek]

Whenever we know it can be applied

Honestly, I have troubles answering as I feel this question is putting things on the head. We start with a lattice. We research its crystallic structure using crystallographic methods. Once we know that it is FCC or HCP lattice, we know spherical packing will work. So we don't start with spherical packing and look where to apply it, but we start with a lattice and check if spherical packing (or some other sctructure) can be used to describe its properties.

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[mahela007]

So spherical packing is not a universal model which all lattices must follow?

 

[Borek]

Definitely not.

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[mahela007]

Well, my chemistry textbook (Advanced chemistry by Raymond Chang 8e) says that the general geometrical requirements of crystal formation can by understood by spherical packing. What does that mean?