when some of lattice sites are vacant in any non- ionic said the crystal is said t have vacancy defect and due to decrease in number of particles present in crystal lattice the density of crystal decreases.
B . simple interstiital defect are shown by non- ionic solids in which constituent particles is displaced from its normal site to an interstitial site Hence density of soild increases .
C . Fremkel defect is shown by ionic solids in whcih smaller ions get dislocated from its normal site to its interstitial site which lead to decrease its density .
D. Schottky defect is shown by ionic solids in which equal number of cartion and anion get missed from ionic solids and thus. density of solid decreases.
