Sodium chloride structure, molecular model. Sodium chloride (common salt) consists of a cubic lattice of sodium (small spheres) and chlorine (green) ions and has the chemical formula NaCl. Each positively-charged sodium ion (symbol Na+) is surrounded by six negatively charged chlorine ions (symbol Cl-) and vice versa. The attractions between the positive and negative ions are the bonds that hold the lattice together and give salt its characteristic crystal structure.