Ferric oxide crystallises in a hexagonal close-packed array of oxide i

1.	Ferric oxide crystallises in a hexagonal close-packed array of oxide ions with two out of every three octahedral holes occupied by ferric ions. Derive the formula of the ferric oxide.
Answer» O^2- ions form cubic close packed lattice Number of O^2- = 8 x \(\frac{1}{8}\) = 1 Number of Fe³⁺ = \(\frac{2}{3}\) octahedral voids = \(\frac{2}{3}\) Formula of the compound = \(Fe^{3+} + \frac{2}{3}O^{2-} = Fe_2O_3\)

Ferric oxide crystallises in a hexagonal close-packed array of oxide ions with two out of every three octahedral holes occupied by ferric ions. Derive the formula of the ferric oxide.

Answer»

O^2- ions form cubic close packed lattice

Number of O^2- = 8 x \(\frac{1}{8}\) = 1

Number of Fe³⁺ = \(\frac{2}{3}\) octahedral voids = \(\frac{2}{3}\)

Formula of the compound = \(Fe^{3+} + \frac{2}{3}O^{2-} = Fe_2O_3\)