Among the following compounds, a normal spinel is

Q. Among the following compounds, a normal spinel is

(A) MgFe2O4

(B) ZnFe2O4

(C) CoFe2O4

(D) CuFe2O4

Ans: ZnFe2O4

Solution: A spinel compound is made up of eight FCC unit cells with a 2x2x2 oxygen ion configuration. According to the spaces occupied by the cations in the structure, they can be classified into two types- normal or inverse. ZnFe2O4 has Fe(III) oxidation state of Iron, Zn2+ has CFSE value = 0 therefore, they will be acting like a normal spinel compound here. The general formula of normal spinel compounds – AB2X4.