Covalent compounds typically exhibit low melting points due to their composition of small molecules that are held together by relatively weak intermolecular forces.

Covalent compounds are formed when two non-metal atoms share electrons, resulting in a bond known as a covalent bond. While these bonds are strong, the forces acting between the molecules—referred to as intermolecular forces—are comparatively weak. When a substance is heated, energy is supplied to overcome these intermolecular forces. Because the intermolecular forces in covalent compounds are weak, only a small amount of energy (or heat) is required to break them. This characteristic explains why covalent compounds generally have low melting points.

The strength of intermolecular forces varies with the size and shape of the molecules involved. Generally, larger molecules exhibit stronger intermolecular forces, leading to higher melting points. Nevertheless, even the largest covalent molecules possess weaker intermolecular forces than those found in ionic compounds, which are held together by strong electrostatic attractions between positive and negative ions. Consequently, ionic compounds typically have significantly higher melting points compared to covalent compounds.

It is important to note that not all covalent compounds have low melting points. For example, substances such as diamond and quartz possess very high melting points because they are classified as network covalent compounds. In these structures, each atom is covalently bonded to several others, creating a vast, interconnected network. This arrangement results in much stronger intermolecular forces, thus requiring more energy to overcome them.

In summary, the low melting points of covalent compounds can be attributed to the weak intermolecular forces that exist between their molecules. These forces can be easily overcome with a minimal amount of heat, leading to the melting of the compound.