What is a defining characteristic of metallic bonds?

A defining characteristic of metallic bonds is the involvement of free electrons that are shared among a lattice of metal cations. This phenomenon is often referred to as "delocalized electrons," where the electrons are not bound to any specific atom but move freely throughout the metal structure. This electron mobility is what gives metals their unique properties, such as electrical conductivity and malleability.

The arrangement of metal cations in a regular lattice structure allows these delocalized electrons to flow easily, which is essential for the conduction of electricity. When an electric field is applied, these free electrons are able to move toward the positive end of the field, resulting in electrical current. Additionally, the flexibility of metallic bonds contributes to the ability of metals to be shaped and stretched without breaking.

This understanding underscores how metallic bonds differ fundamentally from covalent or ionic bonds, which involve the sharing or transfer of electrons between specific atoms, often leading to rigid structures that are less conductive.