Metal deficiency defect is shown by $Fe_{0.93}O$. In the crystal, some $Fe^{2+}$ cations are missing

Question

Metal deficiency defect is shown by $Fe_{0.93}O$. In the crystal, some $Fe^{2+}$ cations are missing and loss of positive charge is compensated by the presence of $Fe^{3+}$ ions. The percentage of $Fe^{2+}$ ions in the $Fe_{0.93}O$ crystals is X (Nearest integer)

Professor PC Thomas Classes · Answer

Let the number of $Fe^{2+}$ be x. To balance the charge of $O^{2-}$: $2x + 3(0.93 - x) = 2 \implies x = 0.79$. The percentage of $Fe^{2+}$ ions is $(0.79 / 0.93) 	imes 100 \approx 84.95\% \approx 85\%$.