Notice that the octahedral holes are along the edges (for a net of three cations) and in the center of the cube (one more cation). Thus we have four anions (FCC) and four cations, which corresponds ...

The structure has face-centered cubic symmetry, and is a little heavy to understand. The general formula is AB 2 O 4. The oxygens form an fcc lattice. The A cations occupy tetrahedral holes, and the B ...