Question

A Compound crystallises in face centered cubic unit lattice in which A occupies corners of a cube B occupies the centre of each face. What
is the formula of the compound

Answer 1

Answer:

Answer is AB3

Explanation:

A atoms occupy the lattice points at the corners of the cube.

There are 8 corners in a unit cell, each contributing one eight to the unit cell.

Number of 'A' atoms in one unit cell = 8×  1/8   =1

The B atoms occupy the centre of each fcc of the cube.

There are 6 face centres in a unit cell, each contributing one half to the unit cell.

Number of B atoms in one unit cell =6×  1/2  =3

The formula of the compound is AB  3

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