Step-by-step explanation:
Crystal lattice is defined as an attractive force which is present within repeated units of an arrangement of ions.
For example, when in a solid NaCl each sodium ion is surrounded by six chlorine ions and each chlorine ion is surrounded by six sodium ions.
Then it means that there are repeated units of sodium and chlorine ions are present.
This arrangement of ions will result in the formation of crystal lattice.
Thus, we can conclude that in solid NaCl, each sodium ion is surrounded by six chlorine ions and each chlorine ion is surrounded by six sodium ions. This arrangement results in a crystal lattice.