Solids

Ionic

• Examples: $NaCl$, $CaC{O}^3$
• Conductive when dissociated in water
• High melting point, brittle

Covalent

• Examples: Diamond
• Great insulators
• Extremely hard
• Extremely high melting point

Molecular

• Examples: Sucrose, candle wax
• Not conductive when dissociated in water
• Low melting point, relatively brittle

Metallic

• Examples: Gold, Copper, Aluminum
• Conductive, transfers heat and electricity
• High melting point, ductile