Which is the incorrect statement?
(a) FeO0.98 has non-stoichiometric metal excess defect
(b) Density decreases in case of crystals with Schottky's defect
(c) NaCI(s) is insulator, silicon is semiconductor, silver is conductor, quartz is piezoelectric crystal
(d) Frenkel defect is favoured in those ionic compounds in which sizes of cation and anions are almost equal
Concept Videos :-
Concept Questions :-
(a) FeO0.98 has non-stoichiometric metal excess defect.
(b) In an ionic crystal of A+B- type, if equal number of cations and anions are missing from their lattice sites, the defect is called Schottky defect. Due to such defect, density of solid decreases. Thus, statement (b) is correct.
(c) NaCl-insulator Silicon (Si) -semiconductor. Silver (Ag) - conductor; Quartz - piezoelectric crystal.
Thus, statement (c) is correct.
(d) In an ionic crystal when an j£n is missing from its lattice site and occupies interstitial site, the defect is called Frenkel defect. This type of defect is seen in those crystals where the difference in the size of cations and anions is very large and their coordination number is low. Thus, statement (d) is incorrect.