Some metallic oxides may contain lead as an impurity. The presence of lead in metallic oxides depends on the specific composition and source of the material. For example, lead oxide (PbO) is a compound that contains lead as a major component, while other metallic oxides such as iron oxide (Fe2O3) or aluminum oxide (Al2O3) may have trace amounts of lead as an impurity. The concentration of lead in these materials can vary greatly depending on the geological source and processing conditions.