The crystal lattice and translational symmetry

An ideal crystal consists of a group of atoms repeated throughout space at the points of an infinite regular three-dimensional lattice, R 1, m, n), generated from a set of three non-coplanar vectors, a, b, and c (known as the lattice parameters), according to eqn (10.1)  

An example of how such restrictions work in three dimensions is provided by the perovskite structure shown in Figs 10.3 and 10.4. Crystals of BaTiOa (23759) are composed of an alternation of the BaO and Ti02 layers shown 

---