In a face centred cubic lattice, atom A occupies the corner positions and atom B occupies the face centre positions. If one atoms of B is missing from one of the face centred points, the formula of the compound is :

In a face centred cubic lattice, atom A occupies the corner positions

1.	In a face centred cubic lattice, atom A occupies the corner positions and atom B occupies the face centre positions. If one atoms of B is missing from one of the face centred points, the formula of the compound is :
Answer» `AB_(2)` `A_(2)B_(3)` `A_(5)B_(5)` `A_(2)B` SOLUTION :Contribution by atoms A on the CORNERS ` 4= 8 xx 1/8 =1 ` Contribution by atoms B on the FACE CENTRES ` 5 xx 1/2 = 5/2 ` ( Total atoms on face centres = 6. As one atoms is missing , atoms actually present = 5) : Ration of A: B = ` 1 : 5/2 = 2: 5` Henece, formula ` = A_(2)B_(5)`