Litharge PbO

Finely divided lead, when heated in air, forms first the lead(II) oxide, litharge , PbO, and then on further heating in an ample supply of air, dilead(II) lead(IV) oxide, red lead , Pb304. Lead, in a very finely divided state, when allowed to fall through air, ignites and a shower of sparks is produced. Sueh finely divided powder is said to be pyrophoric . It can be prepared by carefully heating lead tartrate. 

When cinnamaldehyde, succinic acid and acetic anhydride are heated in the presence of litharge (PbO), the aldehyde and the succinic acid condense to give the dicarboxylic acid (I), which undergoes decarboxylation to give the pale yellow crystalline 1,8-diphenyloctatetrene (II), Kuhn has shown that as the... 

Lead Monoxide. Lead monoxide (litharge), PbO, occurs as a reddish alpha form, which is stable up to 489°C where it transforms to a yellow beta form (massicot). The latter is stable at high temperatures. The solubihty of a-PbO ia water is 0.0504 g/L at 25°C the solubihty of the p-PbO is 0.1065 g/L at 25°C (40). Lead monoxide is amphoteric and dissolves ia both acids and alkahes. In alkahes, it forms the plumbite ion PbO - The monoxide is produced commercially by the reaction of molten lead with air or oxygen ia a furnace. Black or gray oxide is manufactured by the Barton process, by the oxidation of atomized molten lead ia air, as well as by the ball mill process, ia which metallic lead balls of high purity are tumbled ia the mill to form partially oxidized lead particles. 

The losses of lead as litharge (PbO) can be minimized if the impurity elements could be oxidized at an oxygen potential lower than that which causes the oxidation of lead. This can be achieved if the activities of the oxides of the impurity elements in the slag are decreased, for example, by the addition of an oxide which reacts very much more strongly with the oxides of the impurities than it does with lead oxide. Sodium hydroxide is a useful reagent for this purpose and sodium nitrate can be used as the source of oxygen. The reaction involved in this process, known as the Harris process, can be formally written as... 

Laperche et al. (1996) studied the conversion in stirred reactors of soil Pb phases such as litharge (PbO), and cerrusite (PbC03) in soils contaminated with paint spills (Pb = 37,026 mg/kg) to hydroxypyromorphite after the addition of hydroxyapatite. These soil Pb fractions (100 mg) were added with hydroxyapatite (20-40 mg) in 100 mL of H2O at pH 5 and 7.7. Subsequently XRD and SEM identified the formation of hydroxypyromorphite (and possible solid solutions) after 9 to 14 days. 

XRD results of the surface scrapings positively identified both litharge (PbO) and cerussite (PbC03). Differential weathering of the trace elements into similar oxides and carbonates would certainly change the apparent concentrations. Considering the small amount of lead available for analysis, the relatively non-destructive EMPA is likely the better technique. 

One gram of powdered picric acid and as much by volume of litharge (PbO) are mixed carefully on a piece of paper by turning the powders over upon themselves (not by stirring). The mixture is then poured in a small heap in the center of a clean iron sand-bath dish. This is set upon a tripod, a lighted burner is placed beneath it, and the operator retires to a distance. As soon as the picric acid melts and lead picrate forms, the material explodes with an astonishing report. The dish is badly dented or possibly punctured. 

Magnesium oxide (MgO) — low activity Magnesium oxide (MgO) — high activity Litharge (PbO)... 

Procedure Take 56 grams, or 0.25 F. W., of litharge, PbO. Calculate the amount of 6 N nitric acid which would be necessary to convert it into lead nitrate and the amount of water needed to dissolve the salt thus formed. Proceed to prepare lead nitrate, striving to obtain good crystals of as large a size as possible. 

Moisten some litharge (PbO) with water and test with litmus, noting that the litmus is turned blue. Boil the litharge a few minutes with 10 cc. of water, filter, and add hydrogen sulphide solution to the filtrate, noting a little black precipitate. 

Pb304, and it is used in making flint glass (lead crystal) and as a red pigment. It results from the heating of litharge (PbO) in air at 400 °C ... 

There are several oxides of lead, of which the most important are lead monoxide (litharge), PbO, minium or red lead, PbgO, and Jead dioxide, PbOg. 

Bivalent lead oxide, litharge (PbO), is among the oldest PVC stabilizers and its properties include its basicity, its complexing properties and its extremely fine particle size, which facilitates incorporation. The improvements in lead stabilizers over the years can be viewed as improvements on the basic characteristics of litharge, with the yellow colour, of course, being one of the apparent disadvantages, but the greatest deterrent to the use of lead stabilizers is their acute and cumulative toxicity. 

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