Question

(i) What type of non-stoichiometric point defect is responsible for the pink colour of $LiCl$?
(ii) What type of stoichiometric defect is shown by $NaCl$ ?

Answer 1

(i) The metal excess defect caused by anionic vacancies is responsible for the pink colour of $LiCl$.
(ii) The Schottky defect is found in $NaCl$. In this defect, an equal number of cations and anions are missing from their regular sites.