A solid PQ has rock salt type structure in which Q atoms are the corners of the unit cell. If the bo — Solid State Chemistry Question

💡 Solution & Explanation

In rock salt, one ion forms an FCC lattice (4 atoms) and the other occupies octahedral voids (1 at body centre + 12 at edge centres = 4 atoms). If Q is at corners, it forms the FCC lattice so Q = 4. P occupies octahedral voids. If the body-centred P atom is missing, remaining P atoms = $12 \times (1/4) = 3$. The resulting formula is $P_3Q_4$. Therefore, correct answer is C.