Lead CAS 7439-92-1

Introduction：Basic information about Lead CAS 7439-92-1, including its chemical name, molecular formula, synonyms, physicochemical properties, and safety information, etc.

Lead Basic information

• Product Name: Lead
• Synonyms: Lead rod, 5mm (0.2 in.) dia.;Lead wire, 2.0mm (0.08 in.) dia.;Lead in Isooctane standards;c.i.77575;c.i.pigmentmetal4;ci77575;PB STANDARD;Electrolytically refined lead (trace elements)
• CAS: 7439-92-1
• MF: Pb
• MW: 207.2
• EINECS: 231-100-4
• Product Categories: Metals&AlloysAlphabetic;TF - TO;Physical PropertiesAnalytical Standards;R;LeadMicro/Nanoelectronics;Catalysis and Inorganic Chemistry;Industrial Raw Materials;Industrial Raw MaterialsAnalytical Standards;Industrial Raw MaterialsCertified Reference Materials (CRMs);IRMM/BCR Certified Reference Materials;Chemical Synthesis;Electronic Chemicals;LeadMetal and Ceramic Science;Pure Elements;Metals;Inorganics;LApplication CRMs;Metals&AlloysCertified Reference Materials (CRMs);Physical Properties;Alphabetic;Matrix CRMs;Reference/Calibration Standards;Lead;Metal and Ceramic Science;EA - EOReference/Calibration Standards;Metals&Alloys;E;Industrial Raw MaterialsApplication CRMs;metal or element
• Mol File: 7439-92-1.mol

Lead Chemical Properties

• Melting point: 327.4 °C (lit.)
• Boiling point: 1740 °C (lit.)
• density: 1.00 g/mL at 20 °C
• refractive index: 2.881 (632.8 nm)
• storage temp.: Store at +5°C to +30°C.
• solubility: H₂O: soluble
• form: wire
• color: Olive-green or red to brown
• Specific Gravity: 11.288
• Flame Color: Blue-white
• Odor: Odorless gas
• PH: 3.8 (20°C in H2O)
• resistivity: 20.65 μΩ-cm
• Water Solubility: reacts with hot conc HNO3, boiling conc HCl, H2SO4 [MER06]
• Merck: 13,5414
• Exposure limits: TLV-TWA 0.15 mg/m³ as Pb (ACGIH andMSHA), 0.05 mg (Pb)/m³ (OSHA); 10-hTWA 0.1 mg(inorganic lead)/m³ (NIOSH).
• Stability: Stable. Incompatible with strong oxidizing agents, potassium, sodium.
• InChI: 1S/Pb
• InChIKey: WABPQHHGFIMREM-UHFFFAOYSA-N
• SMILES: [Pb]
• Shear Modulus: 4.90 GPa, calculated
• Modulus of Elasticity: 14.0 GPa
• Poissons Ratio: 0.42
• Hardness, Brinell: 4.2, Cast
• Hardness, Vickers: 5.0
• CAS DataBase Reference: 7439-92-1(CAS DataBase Reference)
• IARC: 2B (Vol. 23, Sup 7) 1987
• EPA Substance Registry System: Lead (7439-92-1)

Safety Information

• Hazard Codes: T,Xi,Xn,N
• Risk Statements: 61-33-40-48/20-62-36/38-20/22-51/53-50/53-48/20/22-52/53-34-23/24/25
• Safety Statements: 53-45-61-36/37-36-26-60-36/37/39
• OEB: D
• OEL: TWA: (8-hour) 0.050 mg/m3 [*Note: The REL also applies to other lead compounds (as Pb) -- see Appendix C.]
• RIDADR: UN 3082 9/PG 3
• WGK Germany: 3
• RTECS: OF7525000
• TSCA: TSCA listed
• HazardClass: 8
• PackingGroup: III
• HS Code: 78011000
• Storage Class: 6.1C - Combustible acute toxic Cat.3 toxic compounds or compounds which causing chronic effects
• Hazard Classifications: Aquatic Acute 1 Aquatic Chronic 1 Lact. Repr. 1A STOT RE 1 Oral
• Hazardous Substances Data: 7439-92-1(Hazardous Substances Data)
• Toxicity: LDLO oral (pigeon) 160 mg/kg PEL (OSHA) 0.05 mg/m3 PEL (action level) 0.03 mg/m3 TLV-TWA (ACGIH) 0.05 mg/m3 (PEL and TLV apply to lead and inorganic lead compounds)
• IDLA: 100 mg Pb/m3

Lead Usage And Synthesis

History, Occurrence, and Uses

Lead is one of the oldest metals known to civilization. The uses of some of its alloys and salts have been documented early in history. The element derived its symbol Pb from the Latin word plumbium. The metal is rarely found in nature in its native form; however, it is found in several minerals, such as galena (PbS), anglesite (PbSO4), minium (Pb3O4) and cerussite (PbCO3). Its concentration in the earth’s crust is 12.5 mg/kg and in sea water 0.03mg/L.
Lead has numerous applications as metal, alloys and compounds. The major applications of the metal and its alloys such as solder are as materials of construction for pipe lines, plumbing fixtures, wires, ammunition, containers for corrosive acids and shield against short-wavelength radiation. Another major application is in storage batteries in which both the metal and its dioxide are used. Several lead compounds, such as lead chromate (chrome yellow), lead sulfate (white lead), lead tetroxide (red lead), and the basic carbonate are used in paints.

Chemical Properties

Occurring naturally in the earth’s crust, lead is a heavy bluish-gray metal that is lustrous when freshly cut. It is rarely found as a pure metal but rather is complexed with other elements to form lead compounds. Found in ore with copper, zinc, and silver, lead is found in mineral form as galena (PbS), anglesite (PbSO4), and cerussite (PbCO3). It is easily malleable, smelted, and can be added to other metals to form alloys. Resistant to air and water corrosion, it does not mix easily with many solvents but will react with hot acids such as nitric and sulfuric. It has 4 naturally occurring isotopes as well as 17 that have been produced experimentally. Burning with a bluish-white flame, powdered lead displays pyrophoricity and releases toxic fumes when burned.

Lead has had a multitude of practical uses for over 8000 years and reports of poisoning exist in all ancient civilizations, including Greece, Rome, and China. By the second century in Greece, lead was known to cause colic when swallowed, and lead intoxication also produced paralysis.

Physical Properties

Silvery grey metal with bright luster; face-centered cubic crystals; very soft, malleable and ductile; easily cast, rolled and extruded; density 11.3 g/cm3; Moh’s hardness 1, Brinell hardness 4.0 (high purity metal); easily melted, melts at 327.46°C; vaporizes at 1,749°C; vapor pressure 1 torr at 970°C and 10 torr at 1160°C; poor conductor of electricity; electrical resistivity 20.65 microhm–cm at 20°C and of liquid melt 94.6 microhm–cm at its melting point; viscosity of molten metal 3.2 centipoise at its melting point and 2.32 centipoise at 400°C; surface tension 442 dynes/cm at 350°C; tensile strength 2,000 psi; thermal neutron absorption cross section 0.17 barn; standard electrode potential, Pb2+ + 2e– Pb –0.13V; very resistant to corrosion.

Production

Lead is produced commercially from its principal ore, galena (PbS). The ore is associated with sulfides of several metals including iron, copper, zinc, silver, bismuth, arsenic, antimony and tin. The ore is crushed and ground. It then is selectively separated from gangue and other valuable minerals by one or more processes that include gravity separation and flotation. Selective flotation processes are most commonly employed to remove significant quantities of most metal sulfides, silica, and other impurities. This yields relatively pure galena concentrate containing 50 to 80% lead.

Reactions

The metal is not attacked by hot water. But in the presence of free oxygen, lead(II) hydroxide is formed. The overall reaction is:
2Pb + 2H2O + O2 → 2Pb(OH)2
In hard water, however, the presence of small amounts of carbonate, sulfate, or silicate ions form a protective film on the metal surface, and prevent the occurrence of the above reaction and thus, corrosion of the metal.
Lead does not evolve hydrogen readily with acids. Nitric acid attacks the metal readily, forming lead nitrate and oxides of nitrogen:
3Pb + 8HNO3 → 3Pb(NO3)2 + 2NO + 4H2O
This reaction is faster in dilute nitric acid than strong acid. Hydrochloric acid has little effect on the metal. At ordinary temperatures, lead dissolves slowly in hydrochloric acid, forming a coating of lead(II) chloride, PbCl2 over the metal, which prevents further attack.
At ordinary temperatures, lead is not readily attacked by sulfuric acid. A coating of insoluble lead sulfate formed on the metal surface prevents any further reaction of the metal with the acid. The acid is, therefore, stored in specially designed lead containers. Also, the action of hot concentrated sulfuric acid is very low up to about 200°C. However, at temperatures near 260°C, both the concentrated sulfuric and hydrochloric acids dissolve lead completely. At ordinary temperatures, hydrofluoric acid also has little action on the metal. Formation of insoluble PbF2 prevents dissolution of lead in the acid.
Organic acids in the presence of oxygen react slowly with lead, forming their soluble salts. Thus, acetic acid in the presence of oxygen forms lead(II) acetate:
2Pb + 4CH3COOH + O2 → 2Pb(CH3COO)2 + 2H2O
Lead dissolves in alkalies forming plumbite ion, Pb(OH)42¯ with the evolution of hydrogen:
Pb + 2OH¯ + 2H2O → Pb(OH)42¯ + H2
Lead combines with fluorine, chlorine, and bromine, forming bivalent lead halides:
Pb + Cl2 → PbCl2
Fusion with sulfur at elevated temperatures yields lead sulfide, PbS.
The metal is oxidized to PbO when heated with sodium nitrate at elevated temperatures.
Pb + NaNO3 → PbO + NaNO2
Lead is widely used in storage batteries. Each cell consists of a spongy lead plate as cathode and lead dioxide as anode immersed in the electrolyte sulfuric acid. The overall chemical reaction in the cell during discharge is as follows: PbO2 + Pb + 2H2SO4 → 2PbSO4 + 2H2O

Toxicity

Lead is an acute and a chronic toxicant. Acute effects are ataxia, headache, vomiting, stupor, hallucination, tremors and convulsions. Chronic symptoms from occupational exposure include weight loss, anemia, kidney damage and memory loss. (Patnaik, P. 1999. A Comprehensive Guide to the Hazardous Properties of Chemical Substances, 2nd ed. New York: John Wiley & Sons.) Permanent brain damage has been noted among children. Lead bioaccumulates in bones and teeth. The metal is classified as an environmental priority pollutant by the US EPA.
The action level for lead in drinking water is 15μg/L. Its content in food and house paints is regulated in the USA by the Food and Drug Administration.

Lead in Body

The main body compartments that store lead are the blood, soft tissues, and bone; the half-life of lead in these tissues is measured in weeks for blood, months for soft tissues, and years for bone. Lead in the bones, teeth, hair, and nails is bound tightly and not available to other tissues and is generally thought not to be harmful. In adults, 94% of absorbed lead is deposited in the bones and teeth, but children only store 70% in this manner, a fact which may partially account for the more serious health effects on children. The estimated half-life of lead in bone is 20 30 years, and bone can introduce lead into the bloodstream long after the initial exposure is gone. The half-life of lead in the blood in men is about 40 days, but it may be longer in children and pregnant women, whose bones are undergoing remodelling, which allows the lead to be continuously reintroduced into the bloodstream. Also, if lead exposure takes place over years, clearance is much slower, partly due to the rerelease of lead from bone. Many other tissues store lead, but those with the highest concentrations (other than blood, bone, and teeth) are the brain, spleen, kidneys, liver, and lungs. It is removed from the body very slowly, mainly through urine. Smaller amounts of lead are also eliminated through the faeces and very small amounts in hair, nails, and sweat.

Description

Lead was one of the earliest metals used by humans, withpossible use extending as far back as the seventh millenniumBC, and reaching its preindustrial peak usage during thereign of the Roman Empire, around the beginning of theCommon Era.

Chemical Properties

Lead is a lustrous silvery metal that tarnishes in the presenceof air and becomes a dull bluish gray. The chemical symbol,Pb, is derived from plumbum, the Latin word for waterworks,because of lead’s extensive use in ancient water pipes. Leadhas four electrons in its valence shell, but only two ionizereadily. The usual oxidation state of lead in inorganic compoundsis therefore +2 rather than +4. Lead generally formsstable compounds; the most important ones are lead oxide(PbO) and lead carbonate (PbCO₃)₂. Four stable lead isotopesexist in nature (²⁰⁸Pb , ²⁰⁶Pb , ²⁰⁷Pb, and ²⁰⁴Pb , in order ofabundance). Lead mined from deposits of different geologiceras has entered the environment, so that today there are widevariations and extensive mixture of isotopic ratios of lead incommerce and in the environment. These differences inisotopic ratios may sometimes be used as nonradioactivetracers in environmental and metabolism studies.

Chemical Properties

grey metal granules, shot, foil, sheet or powder

Physical properties

Lead is a bluish-white, heavy metallic element with properties that are more metal-like thanthe properties of metalloids or nonmetals. Lead can be found in its native state, meaning thatelemental metallic lead can be found in deposits in the Earth’s crust. However, most lead isfirst mined as galena ore (lead sulfide, PbS). The galena is mixed with lead sulfate, lead sulfide,and lead oxide and is then roasted at a high temperature. The air supply is reduced, followedby an increase in heat and the vaporization of the sulfates and oxides of lead, which are drawnoff as gases. The molten lead is then recovered.
Lead is only slightly soluble in water. However, it is also toxic. This is the reason lead isno longer used to pipe fresh water into homes. It does not react well with acids, with theexception of nitric acid. Lead’s melting point is 327.46°C, its boiling point is 1,740°C, andits density is 11.342 g/cm³.

Isotopes

There are 47 isotopes of lead, four of which are stable. One of these four is Pb-204, which makes up 1.4% of the natural abundance of lead found on Earth. In reality thisisotope is not stable but has a half-life that is so long (1.4×10⁺¹⁷ years), with some of theancient deposits still existing, that it is considered stable. The other three stable isotopes oflead and their proportion to the total natural abundance are as follows: Pb-206 = 24.1%,Pb-207 = 22.1%, and Pb-208 = 52.4%. All the other isotopes are radioactive.

Origin of Name

From the Latin word alumen, or aluminis, meaning “alum,” which is abitter tasting form of aluminum sulfate or aluminum potassium sulfate.

Occurrence

Lead is the 35th most abundant element on Earth. Although it has been found in its freeelemental metal state, it is usually obtained from a combination of the following ores: galena(PbS), anglesite (PbSO₄), cerussite (PbCO₃), and minum (Pb₃O₄). Lead ores are locatedin Europe (Germany, Rumania, and France), Africa, Australia, Mexico, Peru, Bolivia, andCanada. The largest deposits of lead in the United States are in the states of Missouri, Kansas,Oklahoma, Colorado, and Montana.
One of the most famous mining towns is the high-altitude western city of Leadville,Colorado. The boom started with the gold rush of the 1860s, followed by silver mining in the1870s and 1880s. Today, this city is the site of mining operations not only for lead, but alsofor zinc and molybdenum. At the height of its fame, Leadville had a population of almost50,000 people. Today the population is about 2,500.
Lead is commonly obtained by roasting galena (PbS) with carbon in an oxygen-rich environmentto convert sulfide ores to oxides and by then reducing the oxide to metallic lead.Sulfur dioxide gas is produced as a waste product. Large amounts of lead are also recoveredby recycling lead products, such as automobile lead-acid electric storage batteries. About onethirdof all lead used in the United States has been recycled.

Characteristics

Although lead can be found as a metal in the Earth’s crust, it is usually mined and refinedfrom minerals and ores. Lead is one of the most common and familiar metallic elementsknown. Although it is somewhat scarce, found at proportions of 13 ppm, it is still more prevalentthan many other metals. Lead is noncombustible. and it resists corrosion.
When lead, which is very soft, is freshly cut, it has shiny blue-white sheen, which soonoxidizes into its familiar gray color. Lead is extremely malleable and ductile and can be workedinto a variety of shapes. It can be formed into sheets, pipes, buckshot, wires, and powder.Although lead is a poor conductor of electricity, its high density makes it an excellent shieldfor protection from radiation, including X-rays and gamma rays.

History

Lead is obtained chiefly from galena (PbS) by a roasting process. Anglesite (PbSO4), cerussite (PbCO3), and minim (Pb3O4) are other common lead minerals. Lead is a bluish-white metal of bright luster, is very soft, highly malleable, ductile, and a poor conductor of electricity. It is very resistant to corrosion; lead pipes bearing the insignia of Roman emperors, used as drains from the baths, are still in service. Lead is used in containers for corrosive liquids (such as sulfuric acid) and may be toughened by the addition of a small percentage of antimony or other metals. Natural lead is a mixture of four stable isotopes: ²⁰⁴Pb (1.4%), ²⁰⁶Pb (24.1%), ²⁰⁷Pb (22.1%), and 208Pb (52.4%). Lead isotopes are the end products of each of the three series of naturally occurring radioactive elements: ²⁰⁶Pb for the uranium series, 207Pb for the actinium series, and ²⁰⁸Pb for the thorium series. Forty-three other isotopes of lead, all of which are radioactive, are recognized. Its alloys include solder, type metal, and various antifriction metals. Great quantities of lead, both as the metal and as the dioxide, are used in storage batteries. Lead is also used for cable covering, plumbing, and ammunition. The metal is very effective as a sound absorber, is used as a radiation shield around X-ray equipment and nuclear reactors, and is used to absorb vibration. Lead, alloyed with tin, is used in making organ pipes. White lead, the basic carbonate, sublimed white lead (PbSO4), chrome yellow (PbCrO4), red lead (Pb3O4), and other lead compounds are used extensively in paints, although in recent years the use of lead in paints has been drastically curtailed to eliminate or reduce health hazards. Lead oxide is used in producing fine “crystal glass” and “flint glass” of a high index of refraction for achromatic lenses. The nitrate and the acetate are soluble salts. Lead salts such as lead arsenate have been used as insecticides, but their use in recent years has been practically eliminated in favor of less harmful organic compounds. Care must be used in handling lead as it is a cumulative poison. Environmental concern with lead poisoning led to elimination of lead tetraethyl in gasoline. The U.S. Occupational Safety and Health Administration (OSHA) has recommended that industries limit airborne lead to 50 μg/cu. meter. Lead is priced at about 90￠/kg (99.9%).

Uses

Lead has been known to humankind sinceancient times. It is a major component ofmany alloys, such as bronze and solder. Itis used for tank linings, piping, and buildingconstruction; in the manufacture of pigmentsfor paints, tetraethyllead, and many organicand inorganic compounds; in storage batteries;and in ceramics. Lead levels in manysoils have been range from 5 to 25 mg/kgand in groundwaters from 1 to 50 μg/L.These concentrations may vary significantly.

Uses

Construction material for tank linings, piping, and other equipment handling corrosive gases and liqs used in the manufacture of sulfuric acid, petroleum refining, halogenation, sulfonation, extraction, condensation; for x-ray and atomic radiation protection; manufacture of tetraethyllead, pigments for paints, and other organic and inorganic lead Compounds; bearing metal and alloys; storage batteries; in ceramics, plastics, and electronic devices; in building construction; in solder and other lead alloys; in the metallurgy of steel and other metals.

Uses

Lead has many uses and is an important commercial commodity. One of the most commonuses is in the acid-lead electrical storage batteries used in automobiles. Much of the leadin these devices can be recycled and used again.
In the past, tetraethyl lead was added to gasoline to slow its burning rate in order to preventengine “knock” and increase performance. This caused serious and harmful pollution, and leadhas since been eliminated as a gasoline additive in most countries. Most exterior (and someinterior) house paints once contained high levels of lead as well. Today, the amount of lead inpaint is controlled, with not more than 0.05% allowed in the paint material.
Lead is used to make a number of important alloys. One is solder, an alloy of 1/2 lead and1/2 tin. Solder is a soft, low-melting metal that, when melted, is used to join two or moreother metals-particularly electrical components and pipes.
Babbitt metal is another alloy of lead that is used in the manufacture of wheel bearingsthat reduces friction. Lead is an ingredient in several types of glass, such as lead crystal andflint glass.
TV screens are coated with lead to absorb any radiation projected by the mechanism, andover 500,000 tons of lead is used in consumer electronics (computers, phones, games, and soon). Much of it ends up in solid waste dumps.
Many lead compounds are poisonous; thus, their uses in insecticides and house paints havebeen limited as other less toxic substances have been substituted. For example, lead arsenate[Pb₃(AsO₄], which is very poisonous, has been replaced in insecticides by less harmful substances.

Uses

In worldwide metal use, lead ranks behind only iron, copper, aluminum, and zinc (Howe 1981). Its largest use is in lead-acid storage batteries for motor vehicles and general industry. Lead metal also is commonly used for ammunition, cable covering, piping, brass and bronze, bearing metals for machinery, and sheet lead (ATSDR 1999).
All of the major soluble lead compounds have industrial uses. Lead acetate is used as a water repellent, for mildew protection, and as a mordant for cotton dyes. Lead acetate trihydrate is used in varnishes, chrome pigments, and as an analytical reagent, and lead chloride is used in asbestos clutch or brake linings, as a catalyst, and as a flame retardant. Lead nitrate is used in the manufacture of matches and explosives, as a heat stabilizer in nylon, and as a coating on paper for photothermography. Lead subacetate is used in sugar analysis and for clarifying solutions of organic substances (HSDB 2009).
The insoluble lead compounds also have a variety of uses. Lead azide and lead styphnate both are used in munitions manufacture. Lead carbonate, lead fluoride, lead fluoborate, and lead naphthenate are used as catalysts, with additional uses in the electronic and optical industries (lead fluoride), in coatings for thermographic copying (lead carbonate), as a curing agent for epoxy resins (lead fluoborate), and as a varnish drier (lead naphthenate). Lead phosphate and lead stearate both are used as stabilizers in the plastics industry. Lead iodide and lead sulfate are used in photography; lead iodide is also used in thermoelectric materials, and lead sulfate with zinc in galvanic batteries. Lead oxide and lead sulfide are used in ceramics; lead oxide is also used as a vulcanizing agent in rubber and plastics, and lead sulfide as a humidity sensor in rockets. Lead chromate is used as a pigment in paints, rubber, and plastics; lead tetraoxide is used in plasters, ointments, glazes, and varnishes; and lead thiocyanate is used in the manufacture of safety matches and cartridges. Lead arsenate formerly was used as an insecticide and herbicide, but no current uses were found.
Organic lead (including tetraethyl lead and tetramethyl lead) was widely used in the United States as an anti-knock additive in motorvehicle fuels until the U.S. Environmental Protection Agency initiated a phase-out of leaded gasoline in the early 1970s. By 1988, the total lead used in gasoline had been reduced to 1% of the 1970 level; in 1996, the use of lead in fuel for on-road motor vehicles was totally banned. Despite the legislated end to use of lead as a gasoline additive and reductions in some other uses of lead, overall U.S. lead consumption continued to grow until 1999, mainly because of increased production of lead-acid batteries (ATSDR 1999), but has since been on a general decline (USGS 2009, 2010, Guberman 2010).

Production Methods

The geometric mean soil lead level is 38 mg/kg. Leadrarely occurs in the elemental state, but exists widelythroughout the world in a number of ores, the most commonof which is the sulfide, galena. The other minerals of commercialimportance are the oxides, carbonate (cerussite), andthe sulfate (anglesite), which are much less common.
Lead also occurs in various uranium and thorium minerals,arising directly from radioactive decay. Because certainisotopes are concentrated in lead derivatives from suchsources, both the atomic weight and the density of thesamples vary significantly from normal lead. Lead oresgenerally occur in nature in association with silver andzinc. Other metals commonly occurring with lead ores arecopper, arsenic, antimony, and bismuth. Most of the world production of arsenic, antimony, and bismuth is a result oftheir separation from lead ores. Commercial lead ores maycontain as little as 3% lead, but a lead content of 10% ismost common. The ores are concentrated to ≥ 40% leadcontent before smelting. A variety of mechanical separationprocesses may be employed for the concentration of leadores, but the sulfide ores are generally concentrated byflotation processes.

Definition

lead: Symbol Pb. A heavy dull greysoft ductile metallic element belongingto group 14 (formerly IVB) ofthe periodic table; a.n. 82; r.a.m.207.19; r.d. 11.35; m.p. 327.5°C; b.p.1740°C. The main ore is the sulphidegalena (PbS); other minor sources includeanglesite (PbSO₄), cerussite (PbCO₃), and litharge (PbO). Themetal is extracted by roasting the oreto give the oxide, followed by reductionwith carbon. Silver is also recoveredfrom the ores. Lead has a varietyof uses including building construction,lead-plate accumulators, bullets,and shot, and is a constituent of suchalloys as solder, pewter, bearing metals,type metals, and fusible alloys.Chemically, it forms compoundswith the +2 and +4 oxidation states,the lead(II) state being the more stable.

General Description

Soft silver-bluish white to gray metal.

Air & Water Reactions

Insoluble in water.

Reactivity Profile

In the presence of carbon, the combination of chlorine trifluoride with aluminum, copper, Lead, magnesium, silver, tin, or zinc results in a violent reaction [Mellor 2, Supp. 1: 1956]. A solution of sodium azide in copper pipe with Lead joints formed copper and Lead azide, both are detonating compounds [Klotz 1973]. Sodium acetylide becomes pyrophoric when mixed with metals like Lead. Mixtures of trioxane with 60% hydrogen peroxide in contact with metallic Lead when heated detonated. Lead containing rubber ignited in a nitric acid atmosphere. Lead is incompatible with strong oxidants such as: ammonium nitrate, chlorine trifluoride, hydrogen peroxide, etc.

Hazard

Lead is probably one of the most widely distributed poisons in the world. Not only is themetal poisonous, but most lead compounds are also extremely toxic when inhaled or ingested.A few, such as lead alkalis, are toxic when absorbed through skin contact.
Workers in industries using lead are subject to testing of their blood and urine to determinethe levels of lead in their bodies’ organs. Great effort is made to keep the workers safe.
Unfortunately, many older homes (built prior to 1950) have several coats of lead-basedpaints that flake off, which then may be ingested by children, causing various degrees of leadpoisoning, including mental retardation or even death.
Young children are more susceptible to an accumulation of lead in their systems than areadults because of their smaller body size and more rapidly growing organs, such as the kidneys,nervous system, and blood-forming organs. Symptoms may include headaches, dizziness,insomnia, and stupor, leading to coma and eventually death.
Lead poisoning can also occur from drinking tap water contained in pipes that have beensoldered with lead-alloy solder. This risk can be reduced by running the tap water until it iscold, which assures a fresher supply of water.
Another hazardous source of lead is pottery that is coated with a lead glaze that is notstabilized. Acidic and hot liquids (citrus fruits, tea, and coffee) react with the lead, and eachuse adds a small amount of ingested lead that can be accumulative. Lead air pollution is stilla problem, but not as great as before, given that tetraethyl lead is no longer used in gasoline.However, lead air pollution remains a problem for those living near lead smelting operationsor in countries where leaded gasoline is still permitted.
Even though lead and many of its compounds are toxic and carcinogenic, our lives wouldbe much less satisfying without its use in our civilization.

Health Hazard

The acute toxicity of lead and inorganic lead compounds is moderate to low.Symptoms of exposure include decreased appetite, insomnia, headache, muscle andjoint pain, colic, and constipation. Inorganic lead compounds are not significantlyabsorbed through the skin.
Chronic exposure to inorganic lead via inhalation or ingestion can result in damageto the peripheral and central nervous system, anemia, and chronic kidney disease.Lead can accumulate in the soft tissues and bones, with the highest accumulation inthe liver and kidneys, and elimination is slow. Lead has shown