How does a network solid differ from most other covalent compounds

Covalent compounds are held by intermolecular forces while network solids are held by strong bonds in unit cells which are closely packed together.

Explanation:

Covalent compound molecules are held by vanderwaals forces which are relatively weak but strong enough to hold some covalent molecules together in the solid state. However, network solids contain atom to atom covalent bonds arranged in an orderly manner and regular repeating unit cells to form a rigid three dimensional network solid.