Can someone help me with coordination numbers?

Question

What is the coordination number for each of the following.

(a) Na+ in the NaCl structure,


(b) Zn2+ in the ZnS unit cell,


(c) Ca2+ in the CaF2 unit cell

Answer 1

You need to know the structure of the crystals to do this correctly. For example, in a cubic structure like NaCl, a sodium ion is at each corner of the cube and a chloride ion is in the middle. So the Na+ coordiantion is EIGHT. This is not a math fluke- if you look at the chloride ions, they also form a cube with a sodium ion in the center.

Answer 2

a) 1
b,c idk i need to know it for my final