covalent solid

Covalent solids, also known as network solids, are characterized by a continuous network of covalent bonds extending throughout the material. These bonds are formed when atoms share valence electrons, creating strong, directional bonds, often in a tetrahedral arrangement.12

This extensive network of strong bonds makes covalent solids exceptionally hard and rigid, with very high melting points, as the entire crystal essentially acts as one large molecule. A prime example is diamond, composed of carbon atoms bonded tetrahedrally, making it the hardest known substance. Another form of carbon, graphite, exhibits a layered structure with strong covalent bonds within layers but weaker interactions between them, leading to different properties like lubrication. Other elements like silicon and germanium, as well as certain compounds like gallium arsenide, also form covalently bonded solids, often acting as semiconductors.12