Lithium chloride crystallizes in a face-centered cubic unit cell with chloride ions occupying the lattice points and lithium ions occupying octahedral holes. How many chloride ions surround each lithium ion in LiCl?

6

Explanation:

The coordination number of a particular crystal structure arrangement is defined as the number of nearest neighbor atoms or ions surrounding an atom or ion.

We must note that in salts of the type MX, the coordination number of each ion must be equal. The structure of LiCl is built by placing each unit cell next to another such that ions residing in the corner, edge or face sites are shared between adjacent unit cells. The LiCl is in FCC arrangement.

Hence in LiCl, each Li+ ion is surrounded by 6 chloride ions.