Add yellow spheres to the previous model to fill all tetrahedral holes. F - ions, the model represents a unit cell of CaF 2 . O has this structure. From the name of the structure and the chemical formulas CaF 2 and Na 2 O, describe cation and anion positions in the anti-fluorite structure. The Body Centered Cubic Lattice.
Many elements crystallize with the hcp, ccp, or bcc arrangement of atoms.
Simple Cubic Lattice a. Remove the central red sphere from your unit cell. Use the three bottom shelves to make a fcc lattice at the right side of the kit. The fcc and ccp arrangements are equivalent. The unit cell just constructed is not actually close-packed, however. It is expanded for better visibility.