A crystalline solid is made of X, Y, and Z elements. Atoms of X form fcc packing; atoms of Y occupy octahedral voids while atoms of Z occupy tetrahedral voids. In the simplest formula of the solid if atoms along one body diagonal are removed the number of Z atoms is?

Number of atoms of X at packing site, that is, at corners and face-centers=8×18+6×12=4Number of atoms of Y = 4Number of atoms of Z = 8Two X atoms, one Y atom, and two Z arc removed if atoms along one body diagonal are removed. Number of atoms of X will be =4−18×2=154Number of atoms of Y will be = 4 - 1 = 3Number of atoms of Z will be = 8 - 2 = 6X  : Y  :  Z154  :  3    :  65  :   4   :   8 Simplest formula =X5Y4Z8