In a face centred cubic arrangement of A and B atoms in which ‘A’ atoms are at the corners of the unit cell and .B. atoms are at the face centers, one of the ‘A’ atoms is missing from one corner in the unit cell. The simplest formula of the compound is

Options

A. `A_(7)B_(24)`
B. `A_7 B_8`
C. `AB_3`
D. `A_7B_3`

Answer

A

Explanation

In a fcc arrangement A and B atoms in which ‘ A atoms are at the corners of the unit cell and .B atoms are at the face centres. One of the ‘A atom is missing from one comer is unit cell hence.
Atoms of `A = 7 xx 1/8 = 7/8`
Atoms of `B -6 xx 1/2 = 3`
Emperical formula of compounds is `A_(7)B_(24)`