Crystal structure

1. WELCOME TO OUR
PRESENTATION

2. Group - F
NAME: ID
1.Avijit Bhuyan 141-33-1798
2. Md. Waliullah 141-33-1860
3.Prosenzit Roy Apu 141-33-1856
4.Saiful Islam 143-33-2164
5.Rafiul Azam 143-33-2255

3. Unit Cell
► Smallest unit of volume that contains all the structural and symmetry information to build-up
the macroscopic lattice structure
► Periodic repetition of unit cell > Crystal
► Unit cell structures —
• Simple Cubestructure
• Face-Centered Cubestructure
• Body-Centered Cubestructure
• Hexagonal Close-Packed structure
• Diamond structure
• Zinc Blend(ZnS) structure
• Rock-salt(NaCl) structure
• CsClstructure

4. FCCunitcellBasis atoms lie at each corner and at the center of each face
Examples:Cu, Ag, Al, Au, Ca, γ-Fe (> 912 °C), Ni, Pd, Pt, Rh
Face-Centered Cubic Structure

5. Body-Centered Cubic Structure
BCC unitcellBasis atoms lie at each corner and one at the center of the cell
Examples: Alkali metals (Li, Na, K, Rb), Cr, Mo, W, Mn, α-Fe (< 912 °C), β-Ti (>
882 °C)

6. ►HCP structure
• Two basic layers - A and B
• Inlayer A, spherical atoms are packed as closely as possible.
• Identical layer Bisplaced on top of A, with the spheres taking up the voids on layer A
• Again, another layer A isplaced on top of Band soon
• Stacking sequence >ABAB……
► Hexagonal symmetry
► Examples: Zn, Co, Mn, Ti, Graphite
Hexagonal Close-Packed Structure

7. Hexagonal Close-Packed Structure

8. HCP unit cellHexagonal in structure with 6 atoms
Smallest unit cellHexagonal unit cell
Hexagonal Close-Packed Structure

9. Diamond Structure
Diamond unit cell  FCC structure with 4 additional atoms
with in the cell
Hence,total number of atoms
Can be described as an FCC structure with each lattice point
having a basis of two atoms
Examples: Diamond, Si, Ge, Gray Sn (α-Sn)

10. Diamond Structure

11. Thank You
Everyone