1. Simple Molecular Covalent
Structure
Bonding
Melting/
Boiling Points
Reason
Conductivity
Solubility
Giant Ionic
Eg. NaCl
Ionic bonds throughout lattice
High
Strong electrostatic attraction between oppositely charged ions
Poor when solid ; good when molten or in aqueous solution
Ions in fixed lattice when solid; lattice breaks down and ions become mobile.
Good in polar solvents
Attraction between ions in lattice and polar solvent
Giant Metallic
Eg. Mg
Metallic bonds between positive ions and delocalised electrons
Strong electrostatic attraction between ions and delocalised electrons
Good
Mobile electrons can move to carry charge
Poor
Forces within the molecule are too strong to be broken by solvents
Giant Covalent
Eg. Diamond
Covalent bonds between atoms
Strong covalent bonds between atoms
No mobile electrons or ions
Forces within lattice too strong to be broken by solvents
Simple Molecular Covalent
Eg. Cl2
Intramolecular covalent bonds; van der Waals’ forces between molecules
Low
Weak van der Waals’ between molecules – little energy required
No mobile ions or electrons
Good in non-polar solvents
Van der Waals’ forces can form between the structure and the non polar solvent.