JEE MainChemistrySolid State
In a solid compound, atoms of element Y form a cubic close-packed (ccp) lattice, and atoms of element X occupy some of the tetrahedral voids. The empirical formula of the compound is given as XY ₂ . If the fraction of tetrahedral voids occupied by X is expressed as 1 z , the value of z is
Correct answer
4
Step-by-step solution
Effective number of Y atoms in a ccp lattice = 4. From the empirical formula XY ₂ , the ratio of X to Y atoms is 1:2 . Number of X atoms per unit cell = 1 2 4 = 2 . Total number of tetrahedral voids in a ccp unit cell = 2 4 = 8 . Fraction of tetrahedral voids occupied by X = 2 8 = 1 4 . Comparing with 1 z , we get z = 4 . Answer: 4