In a face centred cubic arrangement of A and B atoms whose A atoms are at the corner of the unit cell and B atoms at the face centres. Once of the A atom is missing from one corner in unit cell. The simplest formula of compound is

Options

A. `A_7B_3`
B. `AB_3`
C. `A_7B_24`
D. `A_(7//8)B_3`

Answer

C

Explanation

Number of atoms of A from corners of unit cell
`=1-1/8=7/8`
Number of atoms of B from faces of unit cell = 3
Thus , A : B :: 7/8 : 3 or 7 : 24 . Thus , formula is `A_7B_24` .