Table salt NaCl has a face-centered cubic FCC crystal structure, also known as the 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. The arrangement forms a repeating pattern of alternating Na+ and Cl- ions, creating a 3D lattice.Iron Fe , on the other hand, has two common crystal structures depending on its temperature. At room temperature, iron has a body-centered cubic BCC crystal structure, known as alpha-iron -Fe or ferrite. In this structure, there is an iron atom at each corner of the cube and one in the center of the cube. When heated above 912C 1674F , iron transitions to a face-centered cubic FCC crystal structure, known as gamma-iron -Fe or austenite.The main difference between the crystal structures of NaCl and Fe is the arrangement of their constituent particles. NaCl has a regular alternating pattern of Na+ and Cl- ions in an FCC structure, while Fe has either a BCC or FCC structure depending on its temperature, with iron atoms occupying the lattice points.