What is the primary characteristic of ionic bonds?

The primary characteristic of ionic bonds is the strong electrostatic attraction between ions. In an ionic bond, one atom donates an electron to another atom, resulting in the formation of positively charged ions (cations) and negatively charged ions (anions). These oppositely charged ions experience a strong electrostatic force of attraction, which holds them together in a stable ionic compound. This interaction is a fundamental aspect of ionic bonding and is what gives ionic compounds their distinctive properties, such as high melting and boiling points, and electrical conductivity when dissolved in water.

In contrast, the sharing of electrons is characteristic of covalent bonds, where atoms form bonds by sharing pairs of electrons, leading to different types of molecular structures. The free movement of electrons generally pertains to metallic bonding, where electrons are delocalized and can move freely throughout a lattice of metal ions. Weak thermal conductivity is not a defining feature of ionic bonds; rather, ionic compounds typically exhibit lower thermal conductivity compared to metals. Thus, the strong electrostatic attraction between ions is what distinctly characterizes ionic bonds.