1. Consider the cubic unit cell of CuzO (a 4.27 A): Assign the red and blue ions as Cu' or O, Draw the unit cell with a red ion at the origin. How would you describe this crystal structure in terms of (a) a lattice plus basis, (b) interpenetrating Bravais lattices, and (c) a close-packed array with interstitial sites filled? Draw a projection of the shifted unit cell onto the b-e face. What is the shortest Cu-Cu distance? Does the crystal have an inversion center?