In a face centred cubic lattice, atom A occupies the corner positions and atom B occupies the face centre positions . If one atom 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 atom of B is missing from one of the face centred points, the formula of the compound is :
Answer» `AB_2` `A_2B_3` `A_2B_5` `A_2B` Solution :Contribution by atoms A on the corners 4=`8xx1/8=1` Contribution by atoms B on the face centres =`5xx1/5=5/2` (Total atoms on face centres=6. As ONE ATOM is missing, atoms actually present=5) `therefore` Ratio of A:B=`1:5/2=2:5` HENCE, FORMULA =`A_2B_5`