The S block is very common in hexaferrites, which has a chemical formula of MeS6O82+. MeS are smaller metal cations, for example, Fe and other transition metals or noble metals. The S block is essentially a slab cut along the (111) plane of an AB2O4 spinel. Each S block has one A layer and one B layer. The A layer features MeS-centered tetrahedron and MeS-centered octahedron, while the B layer is made up of edge-sharing MeS-centered octahedron. Both A and B layers have the same chemical formula of MeS3O42+.
