Question

Which of the following is not true about the ionic solids?

• A. Bigger ions form the close packed structure.
• B. Smaller ions occupy either the tetrahedral or the octahedral voids depending upon their size.
• C. Occupation of all the voids is not necessary.
• D. The fraction of octahedral or tetrahedral voids occupied depends upon the radii of the ions occupying the voids.

Answer 1

The correct option is D The fraction of octahedral or tetrahedral voids occupied depends upon the radii of the ions occupying the voids.

In ionic solids anions (which are normally longer in size than cations forms closed pack array.

The cation occupies one of the two types of holes remaining between the anions (either tetrahedral void or octahedral void).

Depending on the relative sizes of cations and anions, the voids are filled. Occupation of voids depends on the stoichiometry of the compounds. It is not necessary that all voids get filled.

Hence, Option "D" is the correct answer.