Plumbous plumbate

Lead forms two series of compounds corresponding to the oxidation states of +2 and +4. The +2 state is the more common. Compounds of lead(IV) are regarded as covalent, those of lead(II) as primarily ionic. Lead is amphoteric, forming plumbous (Pb(II)) and plumbic (Pb(IV)) salts as well as plumbites and plumbates, respectively. 

Lead forms amphoteric compounds in +2 and +4 valence states, forming plumbous and plumbic salts, such as PbCL and PbCL, as well as plumbites and plumbates, such as Na4Pb03 and Ca2Pb04,. Over a thousand compounds of lead are known which include divalent and tetravalent salts, complexes, and organometaUics. Divalent compounds of lead are far more numerous than the tetravalent compounds. Most compounds, however, result from the reactions involving other lead compounds, rather than elemental lead. Only the reactions involving elemental lead are outlined briefly below. 

Minium (red lead) Plumbous plumbate Pb304 Paint pigment... 

When lead does take part in a chemical reaction, it demonstrates one of two oxidation states, 4+ and 2+. Compounds of the former class are known as lead(IV) or plumbic compounds, while those of the latter class are lead(n) or plumbous compounds. Like aluminum, lead is amphoteric and will react with strong bases. The products of such reactions are known as plumbates and plumbites. 

Let the precipitate settle, and wash two or three times by decantation. Then stir it with 50 ml 3N nitric acid to decompose plumbates and dissolve any plumbous hydroxide. Heat nearly to boiling and wash with hot water, first by decantation and then on the Buchner funnel. Suck it as dry as possible and complete the drying in the desiccator or on the steam bath. The yield should be about 85 per cent. 

The most common coating inhibitors are zinc chromate and plumbous orthoplumbate (red lead), which passivate steel by providing chromate and plumbate ions, respectively, as well as the zinc and lead cathodic inhibitors. These inhibitors are not effective against attack by seawater or brines because the high chloride concentration prevents passivation of steel. 

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