In case of inorganic materials which characterized by positive
tetrahedron with Na+ central body in his positive tetrahedral model,
Na+ plays a role as positive templating agent instead of organic
templates through enhancing nucleation process which leads to
forming smaller crystals [24,25]. It was investigated that adding
a certain amount of Na+ cation can stimulate the growth of crystals
and the crystal size was decreased with the increase of Na2O