If all the atoms touching one face plane are removed in solid `A^(o+)B^(Θ)` having rock salt type structure, then the formula of the compound left and the defect brought by this removal, respectively, is
a. `AB`, Frenkel defect
b. `A_(2)B`, Frenkel defect
c. `AB`, Schottky defect
d. `A_(2)B`, Schottky defect

Options

A. AB, Frenkel defect
B. `A_(2)B` Frenkel defect
C. AB, Schottky defect
D. `A_(2)B` Schottky defect

Explanation

Atoms at the corners and face centre are ‘B’ type atoms
No. of B atom left `=4-((1)/(8)xx4)-((1)/(2)xx1)=3`
‘A’ atoms are present at body centre with probability (share) = 1 and at edge centres with probability
(share)= `(1)/(4)`
Hence no. of A atoms left after removal will be `4-((1)/(4)xx4)=3`
Hence 3 “A type” and 3 “B type” atoms left. So, the formula is AB.