Sodium Chloride is an alkali halide with an fcc crystal structure. The basis is two ions, a sodium cation and a chlorine anion. The crystal lattice parameter is 0.563 nm. The diagram shows both a unit ...

4. Write the charge of each ion. Here are some other examples of dot and cross diagrams for the formation of ions in some ionic compounds – magnesium oxide and calcium chloride.

A dot and cross diagram for sodium chloride suggests that it is made up of pairs of sodium and chloride ions. It is not. A 3D construction model shows how the ions are arranged in a lattice structure.