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Grade 12Physical Chemistry

A unit cell consists of a cube in which there are anions(Y) at each corner and cations (X)at the centre of alteernate faces of the unit cell .What is the formula of compound?

Profile image of Sahil Thakur
7 Years agoGrade 12
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1 Answer

Profile image of Akil S
7 Years ago
FCC - 
Contribution of an atom placed at corner of the unit cell is 1/8.
Therefore, the total no. of anion (B) which are present in a unit cell is = 1/8 × total no. of corners = 1/8 × 8 = 1 anion
Contribution of an atom placed at face centre = 1/2
When cations are placed at the alternative faces, the otal no. of face centred atoms are 2 as shown below in:
So, total no. of cations are = 1/2 × 2 = 1
Thus, the formula of compound is AB.