Voids

IMPORTANT

Voids: Overview

This Topic covers sub-topics such as Octahedral and Tetrahedral Voids, Cubical Voids, Number and Locations of Tetrahedral and Octahedral Voids in FCC, Voids and Their Types and, Triangular Planar Voids

Important Questions on Voids

HARD
IMPORTANT

The distance between an octahedral and a tetrahedral void in pm in FCC lattice would be: 

(Consider edge length is 7 pm)

HARD
IMPORTANT

Column I (Type of crystal) Column II (Location of cations/anions) 
(A) NaCl  (p) Cations-fcc, Anions-all tetrahedral voids 
(B) ZnS (q) Anions-fcc, Cations-all tetrahedral voids
(C) CaF2 (r) Anions-fcc, Cations-all octahedral voids
(D) Na2O (s) Anions-fcc, Cations-alternate tetrahedral voids

 

EASY
IMPORTANT

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

HARD
IMPORTANT

In a compound, atoms of element Y form cubic close packing lattice and those of element X occupy23 times  of tetrahedral voids. The formula of the compound will be

EASY
IMPORTANT

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

MEDIUM
IMPORTANT

In a carbon allotrope having FCC lattice, two atoms are at 0, 0, 0 and a8, a8, a8 coordinates. What is the ratio of C-C bond length distance to the edge length of the unit cell?

MEDIUM
IMPORTANT

 In a compound, oxide ions are arranged in cubic close packing arrangement. Cations A occupy 1/6 of the tetrahedral voids and cations B occupy 1/3 of the octahedral voids. The formula of the compound is
 

EASY
IMPORTANT

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

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EASY
IMPORTANT

Co-ordination number of cation occupying a tetrahedral void is :-

EASY
IMPORTANT

An ionic compound is expected to have a tetrahedral structure if r+/r- lies in the range of

HARD
IMPORTANT

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

EASY
IMPORTANT

The number of tetrahedral sites per sphere in ccp structure is,

EASY
IMPORTANT

The number of octahedral sites per sphere in fcc structure is

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

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

MEDIUM
IMPORTANT

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

MEDIUM
IMPORTANT

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

HARD
IMPORTANT

The number of tetrahedral and octahedral holes in a hexagonal primitive unit cell are: 

MEDIUM
IMPORTANT

In 3D close-packed structures, for every 100 atom, it contains

MEDIUM
IMPORTANT

The empty space between the shaded balls and hollow balls as shown in the diagram is called

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