Bond triangles or
van Arkel–Ketelaar triangles (named after
Anton Eduard van Arkel and J. A. A. Ketelaar) are triangles used to show different compounds in varying degrees of
ionic,
metallic and
covalent bonding. The bond triangle shows that ionic, metallic and covalent bonds are not just particular bonds of a specific type. Rather, bond types are interconnected and different compounds have varying degrees of different bonding character (for example, covalent bonds with significant ionic character are called polar covalent bonds).