Covalent compound bonds
Describe what covalent network substances are and give examples.
Covalent network substances are made of atoms covalently bonded in a continuous three-dimensional lattice.
not consist of discrete molecules.
Examples: diamond, graphite, silicon dioxide (SiO₂), silicon carbide (SiC).
Explain how the structure affects properties like melting point and hardness.
Hard and brittle | Atoms in covalent network substances are held together in a rigid 3D lattice by strong covalent bonds. This makes them extremely hard. However, when force is applied, the structure tends to shatter |
High melting & boiling points | The continuous network of strong covalent bonds requires a large amount of energy to be broken, resulting in very high melting and boiling points. |
Poor conductors of electricity | Most covalent network substances do not have free-moving electrons or ions. Electrons are held tightly in covalent bonds and cannot move, so they cannot conduct electricity (exception: graphite). |
insoluble in water | The strong covalent bonds in the lattice are not broken by interactions with water molecules, making them insoluble |
Compare covalent networks to other types of bonding structures.