NCERT (India) explain stoichiometric defects as those defects which do not disturb the stoichiometry of the solid. Vacancy defects are stated to be under the category of stoichiometric defects. When some lattice sites are vacant, the crystal is said to have a vacancy defect.
My question is: if lattice points are missing in vacancy defects, shouldn't this disturb the stoichiometry of the compound? I think yes but the book states no. Why?