Question

Spinel is an important class of oxides consisting of two types of metal ions with the oxide ions arranged in ccp layers. The normal spinel has one-eighth of the tetrahedral holes occupied by one type of metal ion and one-half of the octahedral holes occupied by another type of metal ion. Such a spinel is formed by $M{g}^{2+}$ , $A{l}^{3+}$ and $O^{2-}$. The neutrality of the crystal is being maintained.

The type of holes occupied by $M{g}^{2+}$ ions is___________.

• A. tetrahedral
• B. octahedral
• C. both A and B
• D. none of the above

Answer 1

The correct option is A tetrahedral

As $O^{2-}$ ions forms ccp, spinel has $4$ negative ions in its structure. So, total positive charge should be $8$.
It has one $M{g}^{+2}$ ion occupying one-eight of the tetrahedral holes and $2$ $A{l}^{+3}$ ions occupying one-half of the octahedral holes. So, the compound is $MgA{l}_2{O}_4$.
Hence option A is correct.