Introduce the characteristics of covalent bonding and covalent materials.不超过200字

Covalent bonds involve the sharing of electrons between atoms to achieve stability, typically following the octet rule. Bonds are directional, strong, and can be either nonpolar or polar based on electronegativity differences. Covalent materials have high melting and boiling points due to strong bond strengths. They exhibit low electrical conductivity, are often insoluble in water, and can be either hard or soft, depending on the nature of the bonding and structure. These materials include network solids like diamond and various molecular solids.