describe the structure of ionic crystals in which the size of the cation and anion are quite different. the larger ions take corner positions of a body-centered cubic cell with the smaller ions in the center of the cube. the smaller ions take the corner positions of a body-centered cubic cell with the larger ions in the center of the cube. the larger ions take the corner positions of a face-centered cubic cell with the smaller ions in the faces of the unit cell. the larger ions and smaller ions take alternating positions in a simple cubic structure. the larger ions assume a close-packed structure with the smaller ions in the cavities of that structur
