FCC Lattice of Metals and Insulators Metals Are“Closed Packed”Atomic Spheres Insulators Arise from Binary Compounds with “Holes”Filled in FCC Lattice XⅫ1-5FCC Lattice of Metals and Insulators • Metals Are “Closed Packed” Atomic Spheres • Insulators Arise from Binary Compounds with “Holes” Filled in FCC Lattice XII-5