What kind of bond is formed when the electronegativity difference is more than 1.7?

The formation of a bond with an electronegativity difference greater than 1.7 typically leads to the creation of an ionic bond. This type of bond occurs when one atom donates an electron to another atom, resulting in the formation of positively and negatively charged ions. The substantial difference in electronegativity means that one atom has a much stronger ability to attract electrons compared to the other.

In ionic bonding, the atom with higher electronegativity (often a nonmetal) attracts electrons from the atom with lower electronegativity (usually a metal). This transfer of electrons results in the formation of charged ions, which are held together by the electrostatic forces of attraction between oppositely charged ions. This characteristic is distinct from polar covalent bonds, where electrons are shared but not equally, typically arising from smaller electronegativity differences, and from pure covalent bonds, where electrons are shared equally due to similar electronegativities. Metallic bonds also differ fundamentally, as they involve a "sea of electrons" shared among a lattice of metal cations, rather than the transfer or unequal sharing of electrons between distinct atoms.