* Electro negativity difference: Lead (Pb) is a metal with a low electronegativity, while oxygen (O) is a nonmetal with a high electronegativity. This significant difference in electronegativity leads to the transfer of electrons from lead to oxygen.

* Formation of ions: The lead atom loses two electrons to become a Pb²⁺ cation, while the oxygen atom gains two electrons to become an O²⁻ anion.

* Electrostatic attraction: The oppositely charged ions (Pb²⁺ and O²⁻) attract each other through strong electrostatic forces, resulting in an ionic bond.

Therefore, lead oxide is held together by the strong electrostatic attraction between positively charged lead ions and negatively charged oxide ions.