Q49 barium titanate (batio crystal has a cubic perovskite structure, where the ba ions are at the vertices of a unit cube, the o ions are at the centre

Q49 Barium Titanate (BaTio crystal has a cubic perovskite structure, where the Ba ions are at the vertices of a unit cube, the O ions are at the centres of the faces while the Ti is at the centre. The number of optical phonon modes of the crystal 1s (a) 12 (b)15 T Ba 0 (c) 5 (d)18 Ans (o).