Question

Problem 1.2 A compound made of elements C and D crystallizes in fce structure. Atoms of C are present at the corners of the cube. Atoms of D are at the centres of faces of the cube. What is the formula of the compound? using log table
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Answer 1

Answer:

D atoms are present at the centres of six faces of unit cell. Each face-centre atom is shared between two cubes. Hence, centribution of each face centre atom to the unit cell is 1/2 atom. The number of D atoms that belong to unit cell = 1/2×6 =3There are one C atom and three D atoms in the unit cell.