Question

A cubic unit cell contains manganese ions at the corners and fluoride ions at the centre of each edge, then what is the empirical formula ?

• A. $Mn{F}_5$
• B. $Mn{F}_6$
• C. $Mn{F}_2$
• D. $Mn{F}_3$

Answer 1

The correct option is D $Mn{F}_3$

Ans: Manganese are at Cerner

fluoride ions at the centre of

each edge.

No. of corner=8

Mangenese present $=8\times \frac{1}{8}=1$

fluoride ions at 12 edges $=12\times \frac{1}{4}=3$

Empirical formula$=\mathrm{Mn}{F}_3$