A sample of wustite is experimentally found to have the non-stoichiometric composition . What is the — Solid State Chemistry Question

💡 Solution & Explanation

Let there be 100 $O^{2-}$ ions. Total negative charge = $200$. Therefore, total positive charge on 93 Fe ions must be $+200$. Let $x$ be the number of $Fe^{3+}$ ions and $(93-x)$ be the number of $Fe^{2+}$ ions. $3x + 2(93 - x) = 200 \implies x + 186 = 200 \implies x = 14$. The percentage of $Fe^{3+}$ is $\frac{14}{93} \times 100 \approx 15.05\%$. Rounded to the nearest integer, it is 15.