Sodium chloride NaCl , commonly known as table salt, has a crystal structure called the face-centered cubic FCC lattice or cubic close-packed CCP structure. In this structure, each sodium Na+ ion is surrounded by six chloride Cl- ions, and each chloride ion is surrounded by six sodium ions. This arrangement forms a three-dimensional repeating pattern, resulting in a stable and highly symmetrical crystal lattice.The formation of the NaCl crystal structure can be explained by the ionic bonding between sodium and chloride ions. Sodium Na has one electron in its outermost shell, while chlorine Cl has seven electrons in its outermost shell. When sodium and chloride come into contact, sodium loses its outermost electron, forming a positively charged sodium ion Na+ , and chlorine gains that electron, forming a negatively charged chloride ion Cl- . This transfer of electrons results in the formation of an ionic bond between the Na+ and Cl- ions.The electrostatic attraction between the positively charged sodium ions and the negatively charged chloride ions causes them to arrange themselves in a way that maximizes the attractive forces and minimizes the repulsive forces. This leads to the formation of the face-centered cubic lattice structure, where each ion is surrounded by six ions of the opposite charge, creating a stable and energetically favorable crystal structure.