Brown lead oxide

Bronsted theory See Bronsted-Lowry theory. bron-steth, the-3-re brown lead oxide See lead dioxide. braun led ak.sTd ... 

Synonyms lead(lV) oxide lead peroxide lead superoxide brown lead oxide plattnerite... 

Lead(IV) oxide, PbOj. Chocolate brown (electrolytic oxidation of Pb(II) salts). Used as an oxidizing agent. 

H. E. Brown, Zinc Oxide, Properties and Applications, International Lead Zinc Organization, Inc., New York, 1976, pp. 56—59. 

Brown, H. E. Lead Oxide Properlies and Applicalions, ILZRO, New York 194-234 (1985)... 

It was there that he discovered a new metal which, because of the red color that its salts acquire when heated, he named erythronium (44). Upon further study, however, he decided that he was mistaken, and that the brown lead ore from Zimapan was a basic lead chromate containing 80.72 per cent of lead oxide and 14.80 per cent of chromic acid (12). His paper therefore bore the modest title, Discovery of chromium in the brown lead of Zimapan (21). In 1805 Collet-Descotils confirmed del Rio s analysis (22), and for twenty-five years no more was heard of the new element, erythronium. 

Since the properties of erythronium closely resembled those which Fourcroy had ascribed to the recently discovered metal chromium, del Rio lost confidence in the importance of his discovery and concluded that his supposed new element was, after all, nothing but chromium (11). In a note to his translation of Kars ten s Mineralogical Tables he wrote (7, 9,12) .. . but, knowing that chromium also gives by evaporation red or yellow salts, I believe that the brown lead is a yellow oxide of chromium, combined with excess lead also in the form of the yellow oxide. ... 

LEAD OXIDE BROWN, FREE FROM MANGANESE... 

Dilute hydrochloric acid Lead (II) acetate or nitrate Cobalt nitrate Mercury Hypochlorites, OCh Yellow coloration, followed by chlorine gas evolution Brown lead (IV) oxide forms upon heating Black precipitate of cobalt (II) hydroxide On shaking slightly acidified solution of a hypochlorite with Hg, a brown precipitate of mercury (II) chloride is formed... 

Procedure Spread 25 grams of lead monoxide in a thin layer on an iron or aluminum plate 2-4 mm. thick. Either use the variety of lead oxide which has not been fused and is known under the name of massicot, or use lead carbonate, which on being heated yields a very pure and finely divided lead monoxide. Heat the lead oxide over a ring burner so adjusted that the flames do not quite touch the metal plate. The plate must be kept just below a perceptible red heat. Continue the heating for 6 hours or more and turn over the powder frequently with an iron spatula. When the change is complete, the product is dark brown when hot, a bright scarlet-red when partly cooled, and a somewhat less brilliant red when entirely cold. 

CYP450s include steroid hormones and lipid-soluble drugs (Brown, 2001). Oxidative reactions frequently lead to the formation of highly reactive epoxides. These toxic metabolites are usually detoxified rapidly by phase II conjugation or other mechanisms, such as microsomal epoxide hydrolases (Pineiro-Carrero and Pineiro, 2004 Watkins, 1999). 

SYNS BIOXYDE de PLOMB (FRENCH) C.I. 77580 LEAD BROWN LEAD(TV) OXIDE LEAD OXIDE BROWN LEAD PEROXIDE (DOT) LEAD SUPEROXIDE PEROXYDE de PLOMB (FRENCH)... 

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