This presentation slide gives you the general idea about the crystal strustures and their defects.

2. AREGULAR THREE DIMENSIONALARRANGEMENT OF CONSTITUENT PARTICLES
REPRESENTED BY POINT IN SPACE, IS KNOWNAS CRYSTAL LATTICE.
THEREARE ONLY 14 THREE DIMENSIONAL LATTICES WHICHARE KNOWNAS
BRAVAIS LATTICES
CRYSTAL LATTICE

3. UNIT CELL
The Smallest portion of a crystal lattice is known as Unit Cell
which when repeated in different direction generates the
complete lattice.

4. TYPES OF CRYSTAL
SYSTEM
There are 7 types of Crystal Systems :-
● Cubical Crystal System
● Tetragonal Crystal System
● Hexagonal Crystal System
● Rhombohedral Crystal System
● Orthorhombic Crystal System
● Monoclinic Crystal System
● Triclinic Crystal System

5. CUBIC CRYSTAL
SYSTEM
Axial Relationship -> a=b=c
Inter axial angle -> α=β=γ

6. HEXAGONAL CRYSTAL
SYSTEM
Axial Relationships -> a=b≠c
Inter axial Angles -> α=β=90̊, γ=120

7. TETRAGONAL
CRYSTAL SYSTEM
Axial Relationships -> a=b≠c
Inter axial Angles -> α=β=γ=90̊

8. RHOMBOHEDRAL
CRYSTAL SYSTEM
Axial Relationships -> a=b=c
Inter axial Angles -> α=β=γ≠90̊

9. ORTHORHOMBIC
CRYSTAL SYSTEM
Axial Relationships -> a≠b≠c
Inter axial angles -> α=β=γ=90̊

10. MONOCLINIC
CRYSTAL SYSTEM
Axial Relationships -> a≠b≠c
Inter axial Angles -> α≠90̊ , β=γ=90̊

11. TRICLINIC CRYSTAL
SYSTEM
Axial Relationships -> a≠b≠c
Inter axial Angles -> α≠β≠γ≠90̊

12. DEFECTS IN SOLIDS
Vacancy Defect - This defect develops in any crystal when
some lattice sides are empty. As a result, the density of the
substance decreases.
This Defects may develops when some substance heated.

13. DEFECTS IN SOLIDS
Interstitial Defect – This defect develops when some
constituents particles occupy interstitial sides. Due to this
defects, the density of the crystal increases.

14. DEFECTS IN SOLIDS
Frenkel Defect – In this Defect smaller ion (cation) is
dislocated from its original sides to an interstitial sides due
to which vacancy defect is developed at its original location.
It is also called with the name Dislocation Defect.

15. DEFECTS IN SOLIDS
Schottky Defect – This defect develops when some cation &
anion are missing from their lattice sides due to which the
crystal remain neutral. So, it is a vacancy defect in ionic
solid.
Due to Schottky Defect, the density of the crystal decreases.
This defect is shown by those ionic crystal solids in which
the cations & anions are of almost similar sizes.
AgBr shows both frenkel & Schottky Defect.