What is the formula ofa compound in which the element Y form ccp lattice and atoms of X occupy `(2)/(3) rd` of tetrahedral voids ?

Explanation

Number of tetrahedral voids formed `= 2 xx` No. of atoms of element Y
No. of atoms of element Y in the ccp unit cell = 4
No. of tetrahedral voids by atoms of Y =` 2 xx 4 =8 `
`:.` No. of tetrahedral voids occupied by atoms of
`X = ( 2)/( 3) xx 8 = ( 16)/( 3)`
Ratio of the no. of atoms of X and Y is `= ( 16)/( 3) : 4 `
`= 16 : 12 `
` = 4:3 `
Hence, formula would be `X_(4) Y_(3)`