In which of the following ionic solids, the cations and anions are arranged in a body-centred cubic (BCC) structure?
also known as caesium chloride, has a body-centred cubic (BCC) arrangement, where the caesium cations are at the centre of the cube and the chloride anions are at the corners of the cube.
(sodium chloride) has a face-centred cubic (FCC) structure (calcium fluoride) has a fluorite structure, and (magnesium oxide) has a rock salt structure.
Hence, the correct answer is an option (1)