A typical covalent, simple molecular compound is made of small molecules. Inside each molecule the atoms are joined by strong covalent bonds. Between one molecule and the next there are only weak forces, called intermolecular forces.
When a simple molecular substance melts or boils, it is the weak intermolecular forces between the molecules that are overcome. The covalent bonds inside the molecules stay intact. Only a small amount of energy is needed to do this, so simple molecular compounds have low melting points and low boiling points. Many, such as methane, are gases or liquids at room temperature.
Simple molecular compounds are poor conductors of electricity. Their molecules have no overall charge, and there are no ions or delocalised electrons that are free to move and carry charge.
