Packing in Voids of Ionic Solids
Packing in Voids of Ionic Solids: Overview
This topic covers concepts, such as, Rock Salt Structure,Zinc Blende Structure,Radius Ratio etc.
Important Questions on Packing in Voids of Ionic Solids
In which of the following crystals, the alternate tetrahedral voids are occupied?

Ionic radii of cation and anion are and respectively. These ions are allowed to crystallise into an ionic solid. This crystal has cubic close packing for . is present in all octahedral voids. The edge length of the unit cell of the crystal is _____ . (Nearest Integer)

In (Zinc Blende structure), is introduced in available tetrahedral voids. Then ions are removed from a single body diagonal of the unit cell. What will be the molecular formula of the unit cell?

The structure of is different from though both have similar formula. Give reason.

The edge length of ( structure) is . Assuming contact along the cell edge, calculate the radius of ion

The edge length of unit cell of sodium chloride is . If the size of ion , the size of ion would be


In a structure, if positions of atoms and atoms are interchanged, then in the new unit cell

If radius of an octahedral void is and atomic radius of atoms assuming cubical close packing is . Then the relation between and is

If radius of a metal atom is and radius of an electronegative atom is , then in the unit cell

A student finds a crystal of having mass He uses some of it to prepare solution. How many unit cells are remained in the crystal ?

A crystal is made of particles and . A forms packing and occupies all the octahedral voids. If all the particles along the plane as shown in figure are removed, then, the formula of the crystal would be :

A solid compound has structure. If the radius of the cation is , the radius of the anion in pm will be
(Round of the answer up to four significant figures)

If the radius ratio is in the range of , then the coordination number will be

In solid, if all the ions are removed along one of the axes joining the centres of any two diagonally opposite edges in a unit cell, then the resulting stoichiometry of the solid is


In crystal, the number of nearest neighbours of each ions are:-

An ionic solid crystallises in rock salt structure with density . If the radius of cation and anion is and respectively, then the molar mass of solid is

The radius of ion is and ion is . The co-ordination number of ion is:-

The tetrahedral voids formed by arrangement of ions in rock salt structure are
