A solid is formed by two elements P and Q. The element Q forms cubic close packing and atoms of P occupy one third of tetrahedral voids. The formula of the compound is [AMU 2010]

Effective number of Q for FCC = 4 since tetrahedral voids are equal to the double of atoms in FCC lattice, so no. of tetrahedral voids =8 Effective contribution of P, 1 8 8 3 3 p Z x Formulae of compound = 8 4 2 3 3 P Q PQ Hence the correct answer is option (c)