Question

$F{e}_3{O}_4$ has inverse spinel structure. What is not true about this solid?

• A. $F{e}^{3+}$ ions are equally distributed between octahedral and tetrahedral voids
• B. Tetrahedral voids are equally distributed between $F{e}^{2+}$ and $F{e}^{3+}$
• C. Number of $O^{-2}$ >$F{e}^{3+}$ > $F{e}^{2+}$
• D. Coordination number of $F{e}^{3+}$ = 8 throughout the unit cell

Answer 1

Answer: (B), (D)

Coordination number of $F{e}^{3+}$ = 8 throughout the unit cell

$F{e}_3{O}_4$ has inverse spinel structure.
$O^{2-}$ ions forms FCC unit cell.
$F{e}^{3+}$ occupies $\frac{1}{8}\left(TV\right)=OneF{e}^{+3}$
$F{e}^{2+}$ occupies $\frac{1}{4}\left(OV\right)=OneF{e}^{+2}$
$F{e}^{3+}$ occupies $\frac{1}{4}\left(OV\right)=OneF{e}^{+3}$