1. The Nature of Solids

2. General Properties Orderly… Repeating… arrangement of particles
Fixed location
geometric

3. Structure Most solids are crystalline Form a Crystal Lattice
Orderly, repeating, 3-D pattern of particles
Unit Cell
Smallest group within a lattice that retains the geometric shape of the crystal.

4. Cubic Crystal Lattices

5. Allotropes Some solid substances can exist in more than one form.
Diamond…
Graphite…
Coal

6. Crystal Structure of Diamond
The ball-and-stick diagram shows the crystal structure of diamond, a covalent network solid. Each corner or intersection of lines represents a carbon atom. Notice the tetrahedral arrangement at each carbon atom.

7. Graphite Structure
The ball-and-stick diagram of graphite shows the that the carbon atoms form a network of hexagonal rings within each plane. The planes are stacked in layers that can slide over one another.

8. Buckeyballs (Fullerenes) C60
The ball-and-stick diagram shows carbon atoms in a spherically shaped arrangement like the surface of a soccer ball with 60 carbon atoms in interconnected 5- and 6-member rings forming buckminsterfullerenes, or Buckyballs. They were first prepared in 1985.
Buckminsterfullerene molecule

9. Nanotube Cable
The diagram shows a ball-and-stick model of a nanotube with carbon atoms in six-membered rings bonded in honeycomb-shaped, cylindrical structures. Nanotubes having strands narrower than a human hair and 10 times stronger than steel were first prepared in 1997.

10. Definition
Allotropes are two or more different molecular forms of the same element in the same physical state but different properties.
Only a few elements have allotropes:
Carbon, Phosphorous, Sulfur, and Oxygen
Metalloids : Boron and Antimony

11. Non-Crystalline Solids
A amorphous solid lacks an ordered internal structure.
Atoms are randomly arranged.
Examples include:
Rubber, plastic, and asphalt
Coal and Glasses

12. More on Glasses
A glass is a transparent fusion product of inorganic substances that have cooled to a rigid state without crystallizing.
Glasses do NOT melt at a definite temperature; instead they gradually soften when heated.
Shatter → fragments have irregular angles and jagged edges

13. Molecular Structure of a Crystal

14. Molecular Structure of a Glass