as we will see in following sections,it is also possible for one or more lattice defects to associate with one anohther ,that is ,to cluster together .These are indicated byy enclosiing he components of such a cluster in parenthesis.As an example,(xx) would represent a Schlttky defect in which the two vacancies were associated as a vacancy pair.
It is seen that the normal symbol for a chemcial element represents the species involved ,and the subsript represents the position of the atom in the structure.
急!高分悬赏。