Which of the following is NOT a characteristic of covalent network solids?

Covalent network solids are known for several defining characteristics, one of which is their inability to conduct electricity. Unlike metals, which have free-moving electrons that allow them to conduct electricity effectively, covalent network solids have tightly bonded atoms, resulting in no free charge carriers to facilitate electrical conductivity. This property underlines the choice that states they do not conduct electricity, distinguishing them from other types of solids.

In contrast, these solids are typically insoluble in water due to their strong covalent bonds, which do not easily break in the presence of water. They also feature very high melting points, attributed to the strength of the covalent bonds throughout the network, which require significant energy to break. Furthermore, these solids are made up of strong covalent bonds that create a stable and rigid structure, further contributing to their high melting points and insolubility.