lead acetate

Lead(II) acetate
IUPAC name	Lead(II) acetate
Systematic name	Lead(II) ethanoate
Other names	Plumbous acetate, Salt of Saturn, Sugar of Lead, lead diacetate
Identifiers
CAS number	301-04-2 Y, 6080-56-4 (trihydrate) 51404-69-4 (Basic)
Properties
Molecular formula	Pb(C2H3O2)2
Molar mass	325.29 g/mol (anhydrous) 379.33g/mol (trihydrate)
Appearance	White powder or colorless, efflorescent crystals
Density	3.25 g/cm3 (anhydrous) 2.55 g/cm3 (trihydrate) 1.69 g/cm3 (decahydrate)
Melting point	280 °C (anhydrous) 75 °C (trihydrate) 22 °C (decahydrate)
Solubility in water	44.39 g/100 mL (20 °C) 211 g/100 mL (50 °C)[1]
Solubility	anhydrous soluble in alcohol; hydrates insoluble in alcohol
Refractive index (nD)	1.567 (trihydrate)
Structure
Crystal structure	Monoclinic
Hazards
Main hazards	Neurotoxic, Probable Human Carcinogen
NFPA 704	1 3 0
Flash point	Nonflammable
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Lead(II) acetate is a chemical compound, a white crystalline substance with a sweetish taste. It is made by treating litharge (lead(II) oxide, PbO) with acetic acid. Like other lead compounds, it is toxic. Lead acetate is soluble in water and glycerin. With water it forms the trihydrate, Pb(CH₃COO)₂·3H₂O, a colorless or white efflorescent monoclinic crystalline substance. Lead(II) acetate is also known as lead acetate, lead diacetate, plumbous acetate, sugar of lead, lead sugar, salt of Saturn, and Goulard's powder (after Thomas Goulard).

The substance is used as a reagent to make other lead compounds and as a fixative for some dyes. In low concentrations, it is the principal active ingredient in progressive types of hair coloring dyes. Lead(II) acetate is also used as a mordant in textile printing and dyeing, as a drier in paints and varnishes, and in preparing other lead compounds.

Historical use

Like other lead(II) salts, lead acetate has a sweet taste, which has led to its use as a sugar substitute throughout history. The ancient Romans, who had few sweeteners besides honey, would boil must (grape juice) in lead pots to produce a reduced sugar syrup called defrutum, concentrated again into sapa. This syrup was used to sweeten wine, and to sweeten and preserve fruit. It is possible that lead acetate or other lead compounds leaching into the syrup might have caused lead poisoning in anyone consuming it.^[2]

Pope Clement II died in October 1047. A recent toxicologic examination^{[citation needed]} of his remains confirmed centuries old rumors that the Pope had been poisoned with lead sugar. It is, however, not clear whether he was assassinated or not.

In 1787 the painter Albert Christoph Dies swallowed, by accident, three-quarters of an ounce (21 g) of lead acetate. His recovery from this poison was slow and incomplete. He lived with illnesses until his death in 1822.^{[citation needed]}

Although its use was already illegal at that time, composer Ludwig van Beethoven probably died of lead poisoning caused by wines adulterated with lead acetate^[3][4].

Mary Seacole applied it among other remedies against an epidemic of cholera in Panama^[5][6].

Sugar of lead has also been used to treat poison ivy.

Lead acetate is no longer used as a sweetener in most of the world because of its recognized toxicity. Modern chemistry has made the substance easy to detect, which has all but stopped the illegal use that continued for several decades after legal use was terminated.

Other uses

Lead acetate, as well as white lead, have been used in cosmetics throughout history, though this practice has ceased in Western countries.^[7] It is still used in men's hair coloring products^[8] like Grecian Formula.

Lead acetate paper is used to detect the poisonous gas hydrogen sulfide. The gas reacts with lead(II) acetate on the moistened test paper to form a grey precipitate of lead(II) sulfide.

Lead acetate solution was a commonly used folk remedy for sore nipples.^[9]

An aqueous solution of lead acetate is the byproduct of the 50/50 mixture of hydrogen peroxide and white vinegar used in the cleaning and maintenance of stainless steel firearm suppressors (silencers). The solution is agitated by the bubbling action of the hydrogen peroxide, and the main reaction is the dissolution of lead deposits within the suppressor by the acetic acid, which forms lead acetate. Because of its high toxicity, this chemical solution must be appropriately disposed by a chemical processing facility or hazardous materials center. Alternately, the solution may be reacted with sulfuric acid to precipitate insoluble lead sulfate. The solid may then be removed by mechanical filtration and is safer to dispose of than aqueous lead acetate.

Biological hazards

Lead(II) acetate, among other lead salts, has been reported to cross the placenta and to the embryo leading to fetal mortality. Lead salts also have teratogenic effect in some animal species.

References

External links

• Case Studies in Environmental Medicine - Lead Toxicity
• Essay on "Lead Poisoning and Rome"
• HowStuffWorks "What Kind of Hair Color Do Men Use?" discussion of progressive dyes containing lead acetate
• National Pollutant Inventory - Lead and Lead Compounds Fact Sheet
• ToxFAQs: Lead
• US Food and Drug Administration (FDA) fact sheet "Lead Acetate in Hair Dye Products"