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 arrangement, each sodium ion Na+ is surrounded by six chloride ions Cl- , and each chloride ion is surrounded by six sodium ions. The ions are arranged in a repeating pattern, with alternating Na+ and Cl- ions, forming a three-dimensional lattice.The crystal structure of sodium chloride significantly affects its physical and chemical properties:1. High melting and boiling points: The FCC lattice structure results in strong electrostatic forces between the positively charged sodium ions and the negatively charged chloride ions. These strong ionic bonds require a large amount of energy to break, leading to high melting 801C and boiling 1413C points for NaCl.2. Brittleness: The ionic bonds in the NaCl lattice are strong, but they are also directional. If a force is applied to the crystal, the ions may shift, causing ions of the same charge to be close to each other. This repulsion between like-charged ions can cause the crystal to break or cleave along specific planes, making it brittle.3. Solubility in water: The NaCl crystal structure is easily disrupted by polar solvents like water. Water molecules, with their partial positive and negative charges, can surround and separate the Na+ and Cl- ions, dissolving the crystal lattice. This is why sodium chloride is highly soluble in water.4. Electrical conductivity: In its solid state, NaCl does not conduct electricity because the ions are held in fixed positions within the crystal lattice. However, when dissolved in water or melted, the ions become free to move, allowing the substance to conduct electricity.5. Formation of cubic crystals: The FCC lattice structure leads to the formation of cubic-shaped crystals, which can be observed in the regular, cube-like shape of salt crystals.In summary, the crystal structure of sodium chloride plays a crucial role in determining its physical and chemical properties, such as its high melting and boiling points, brittleness, solubility in water, electrical conductivity, and the formation of cubic crystals.