What property distinguishes covalent network structures?

Covalent network structures are defined by their unique bonding arrangement, which involves a vast network of covalent bonds extending throughout the material, resulting in specific physical properties. The high melting and boiling points of these structures arise from the strength of the covalent bonds that must be broken to change the state of the material. Because a significant amount of energy is needed to disrupt this extensive network, these substances typically exhibit very high thermal stability.

For example, diamond, which is a covalent network structure, showcases this characteristic with a melting point exceeding 3,500 degrees Celsius. This property distinguishes covalent network compounds from other molecular or ionic substances, which often have lower melting points due to weaker intermolecular forces or ionic bonds.

As for the other responses, they describe properties that do not apply to covalent network structures. Many of these structures are not soluble in water, as the strong bonds prevent interaction with polar solvents. Additionally, they generally do not conduct electricity in solid form due to the lack of free-moving charged particles, although some forms, like graphite, can conduct electricity due to their unique arrangement. Lastly, covalent network structures are typically solid at room temperature, rather than gaseous, highlighting their stability and structural integrity.