Question

An ionic compound axby occupy in fcc type of crystal structure.The ion b is at center of each face and the ion a occupies corner of the cube. Calculate the value of x and y. Write the formula of the ionic compound

Answer 1

Let total atoms in this fcc lattice be x

b is at center of each face thus is contributes to *1/6th* of the total atoms i.e. x/6

a is at corner hence is contributes x/8.

Therefore ratio is a:b = 8:6

Hence x= 8

y=6

Answer 2

Answer:

Explation:

In FCC type there are total 4 atoms

According to question the in b is at center of each face that is there are total 6 faces

Each atom at a face is shared be 2 sides

I.e 1/6 × 2 = 3

And atom a occupies a corner of each phase

I.e there are total eight corners

1/8×8 =1

One atom is shared by eight corners of eight different cubic lattice

Therefore

Value of x = 1

Value of y = 3

The formula for ionic compound is

A1B3