Arun
Last Activity: 5 Years ago
In complex terms we can't ever really describe something as been fully ionic or fully covalent but more of a mix of the two. For example, a HCl molecule will have a small amount of ionic bonding character even though we define it as covalent bonding. This is besides the point though... in this case, we generally assume ionic bonds are stronger than covalent.
If you increased the covalent bonding character in a species you are likely to decrease the ionic bonding character resulting in a lower melting point as forces of attraction are now weaker. However, we do see additional bonding occur in species such as vulcanised rubber where you get cross-linking between carbon atoms on adjacent chains. This then obviously increases the melting point as you have not reduced any ionic bonding character.