Chapter 2 Solids
Liquids can be cooled to form a solid, a state of matter where the particles are generally fixed into a particular position. Solids can be crystalline where the particles are arranged in a definite, repeatable, and orderly pattern or amorphous where the particles lack long-range order (i.e. has no repeating patterns) as seen with glass, rubber, many polymers, pitch, and more.
Figure 2.1: Ordered arrangement of particles in a crystalline solid.
Figure 2.2: Disordered arrangement of particles in an amorphous solid.
Solids can be characterized into various types, each exhibiting a set of properties.
| Type | Particles | Attractions | Properties | Examples |
|---|---|---|---|---|
| ionic | ions | ionic | hard, brittle, conducts electricity as a liquid but not as a solid, high to very high melting points | NaCl, Al2O3 |
| metallic | atoms of electropositive elements | metallic | shiny, malleable, ductile, conducts heat and electricity well, variable hardness and melting points | Cu, Fe, Ti, Pb, U |
| covalent network | atoms of electronegative elements | covalent | very hard, not conductive, very high melting points | C (diamond), SiO2, SiC |
| molecular | molecules (or atoms) | IMFs | variable hardness, variable brittleness, not conductive, low melting points | H2O, CO2, I2, C12H22O11 |