Voids
Voids: Overview
This topic covers concepts such as Voids and Their Types, Octahedral and Tetrahedral Voids, Number and Locations of Tetrahedral and Octahedral Voids in FCC, Triangular Planar Voids, and Cubical Voids.
Important Questions on Voids
A compound is formed by two elements and . The element forms ccp and atom occupies of the tetrahedral voids. The formula of the compound is

Column I (Type of crystal) | Column II (Location of cations/anions) |
(A) | (p) Cations-fcc, Anions-all tetrahedral voids |
(B) | (q) Anions-fcc, Cations-all tetrahedral voids |
(C) | (r) Anions-fcc, Cations-all octahedral voids |
(D) | (s) Anions-fcc, Cations-alternate tetrahedral voids |

A molecule have radius ratio of is more than 0.732. Which of the following void is presented in the molecule.

A molecule have radius ratio of is 0.200 . Which of the following void is presented in the molecule.


Right option for the number of tetrahedral and octahedral voids in hexagonal primitive unit cell are:

In a compound, atoms of element form cubic close packing lattice and those of element occupy of tetrahedral voids. The formula of the compound will be

The total number of tetrahedral voids in the face centred unit cell is

In a carbon allotrope having lattice, two atoms are at and coordinates. What is the ratio of bond length distance to the edge length of the unit cell?


In a compound, oxide ions are arranged in cubic close packing arrangement. Cations occupy of the tetrahedral voids and cations occupy of the octahedral voids. The formula of the compound is

For the structure given below the site marked as S is a :-

The number of tetrahedral voids per atom in a crystal lattice is

The number of tetrahedral voids per unit cell in the crystal is

The total number of tetrahedral voids in the face-centred unit cell is _____.

The number of octahedral sites per sphere in fcc structure is

The ratio of close packed atoms to octahedral holes in hexagonal close packing is

The ratio of close packed atoms to tetrahedral holes in cubic packing is

In a solid , having the rock salt structure, atoms form the arrangement and atoms occupy all the octahedral voids. If the atom at body centred octahedral void is missing, then the formula of the compound will be:

In a face centred cubic arrangement of metallic atoms, what is the relative ratio of the sizes of tetrahedral and octahedral voids?
