The spinel structure `(AB_(2)O_(4)` consists of an fcc array of `O^(2-)` ions in which the:

The spinel structure consists of an array of O^(2-) ions in fcc arrangement. Gereral formula of spinel is AB_(2)O_(4) . Cations of A occupy 1/8th the tetrahedral voids and cations of B ions occupy half of the octahedral voids. If oxide ions are replaced by X^(-8//3) ions then number of an ionic vacancy per unit cell will be

The spinel structure consists of an array of O^(2-) ions in fcc arrangement. Gereral formula of spinel is AB_(2)O_(4) . Cations of A occupy 1/8th the tetrahedral voids and cations of B ions occupy half of the octahedral voids. If oxide ions are replaced by X^(-8//3) ions then number of an ionic vacancy per unit cell will be

The structure of [Cu(H_(2)O)_(4)]^(++) ion is

The structure of [Cu(H_2O)_4]^(2+) ions is:

The mineral haematite, Fe_(2)O_(3) consists of a cubic close packed array of oxide ions with Fe^(3+) ions occupying intersitial positions. Predict whether the iron ions are in the octahdral or tetrahedral holes. Radius of Fe^(3+) = 0.65Å .