Answer:
Covalent bonds
Explanation:
There are about three kinds of bonds in chemistry;
Ionic bonds
Covalent bonds
Metallic bonds
Substances that possess ionic and metallic bonds all have high melting and boiling points.
However, covalent molecules often have low melting and boiling points due to weak intermolecular forces in the solid state. They also have a dull appearance and do not dissolve in water.
