In chemistry, a plumbate often refers to compounds that can be viewed as derivatives of the hypothetical anion. The term also refers to any anion of lead or any salt thereof. So the term is vague and somewhat archaic. Examples Halides Salts of , , , etc. are labeled as iodoplumbates. Lead perovskite semiconductors are often described as plumbates. Lead oxyanions Plumbates are formed by the reaction of lead(IV) oxide, , with alkali. Plumbate salts contain either the hydrated hexahydroxoplumbate(IV) or plumbate anion , or the anhydrous anions (meta-plumbate) or (ortho-plumbate). For example, dissolving in a hot, concentrated aqueous solution of potassium hydroxide forms the potassium hexahydroxoplumbate(IV) salt . The anhydrous salts may be synthesized by heating metal oxides or hydroxides with . The most widely discussed plumbates are derivatives of barium plumbate . When doped with some bismuth in place of lead, the material exhibits superconductivity at 13 K. At the time of this discovery, oxides did not show such properties. The surprise associated with this work was eclipsed by the advent of the cuprate superconductors. Binary lead oxides Lead tetroxide ("red lead"), a mixed oxide with formula , may be thought of as lead(II) ortho-plumbate(IV), . Lead sesquioxide, , is also known, and has the structure lead(II) meta-plumbate(IV), . References External links National Pollutant Inventory - Lead and Lead Compounds Fact Sheet Lead(IV) compounds Salts Oxyanions Oxometallates