Crystalline Solids

1. Crystalline Solids BLB 12thChapter 12 Sections 1-3, 5

2. Types of Crystalline Solids p. 464

4. Macroscopic structure depends upon microscopic structure.

5. Pyrite (FeS2, fool’s gold) Fluorite (CaF2) Amethyst (SiO2) – quartz + Fe & Mn

6. Crystalline – atoms, ions, or molecules arranged orderly • Ionic compounds, diamond, sugar, ice • Amorphous – “without form”; lack the order of solids • Glass, plastic, wax, ceramics

7. Crystal Terms • Crystal – • Crytal Lattice – • Unit cell – • Cell dimensions – a, b, c, α, β, γ face edge corner

8. Crystalline lattice in two dimensions

10. Crystalline lattice in three dimensions

11. Filling the unit cell

12. Types of Unit Cells

13. Packing in Crystals • Atoms and ions are represented by spheres. • The spheres stack in different patterns three-dimensionally. • The close packing of spheres maximizes intermolecular force. • The patterns of stacking result in different types of unit cells and lattices.

14. p. 468

15. Types of cubic unit cells

17. Body-centered cubic unit cell of C60

18. Types of cubic unit cells • Three items to determine for each type: • Number of atoms per unit cell • Number of nearest neighbors for each atom • Relationship between sphere radius and the cell edge length, do?

21. Primitive (simple) Cubic _______ atoms per unit cell _______ nearest neighbors

22. Body-centered Cubic _______ atoms per unit cell _______ nearest neighbors

23. Face-centered Cubic(result of close packing) _______ atoms per unit cell _______ nearest neighbors

24. Close packing

25. Close packing

26. Close Packing Cubic close-packed (ccp) ABCABC layers Hexagonal close-packed (hcp) ABAB layers

27. Close packing unit cell types

28. What about the space left over?