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ESTHER ONG PECK SUAN_A19SC0485_MINDMAP 1, Factors in determining crystal…
ESTHER ONG PECK SUAN_A19SC0485_MINDMAP 1
Factors in determining crystal structure
Type of basis
Basis: Consists of an atom, group of atoms or moecule
Added to lattice sites will show crystal structure
Lattice arrangement
Lattice: Regular repeated arrangement of atoms
Set of symmetry operation
Point operation
Refection
n-fold rotations
Inversion
Identity
Combination Operation - combine of translation and point operation
Translation
Crystal axes
Direction
Apply Miller Indices for direction:
1) Define tail as origin
2) Determine a,b,c
3) Remove fraction
4) Enclose in [ ]
Family: enclose in <>
Plane
Miller indices of plane
1) Identify intercepts
2) Take reciprocals
3) Clear fractions
4) Enclose in ()
Family: enclose in ｛｝
Position
1) Choose an origin
2)
3) Position is written as pqs
Crystal Systems
3D
Tetragonal
Rhombohedral
Orthorhombic
Hexagonal
Monocinic
Cubic
Triclinic
2D
Centered Rectangular
Square
Rectangular
Hexagonal
Oblique
Unit Cell - smallest repeating unit of cell
Conventional & non-primitive
More than one lattice point per cell
Body-centered Cubic(BCC)
Face-centered Cubic(FCC)
Wigner-Seitz
Construction:
Primitive
Single lattice point per cell
Simple Cubic(SC)
Solid State Physics
Types of solid materials
Study of materials in solid form.
Properties
Number of atoms per unit cell
Coordination number
Atomic packing factor
Primitive Translation Vectors
Example
Po
Cr. W, Fe
Al, Cu, Pb
0.52
0.68
0.74
6
8
12
1
2
4
Example:
Repeated geometrical pattern
Group of crystals
Does not form a repeated pattern
BCC
FCC
SC
Example:
