Bravais Lattices Considering the seven crystal systems and the three types of special positions (body centered (I), face centered (F), and base centered (A, B, or C)), one might expect 28 Bravais lattices. The orthorhombic crystal system is the only crystal system that displays all four possible options (P, I, F, and base-centered). For the missing cases, we can redefine the unit cell with a smaller one. Consider the C based centered cubic Bravais lattice shown below. The black dots represent the corner lattice points and the blue dots represent the special positions. a. Identify the smaller unit cell that can be used to represent the same set of lattice points on the drawing. b. Identify the Bravais lattice associated with this smaller unit cell. c. Identify the relationship between the original cubic unit cell (lattice parameter, ac, and lattice angles ===90 ) and this smaller unit cell