Chemistry in its element:
Getin Snlead Pband flerovium Fl.
Occurrence and distribution Lead is mentioned often in early biblical accounts. The Babylonians used the metal as plates on which to record inscriptions. The Romans used it for tablets, water pipes, coins, and even cooking utensils; indeed, as a result of the last use, lead poisoning was recognized in the time of Augustus Caesar.
The compound known as white lead was apparently prepared as a decorative pigment at least as early as bce. Modern developments date to the exploitation in the late s of deposits in the Missouri-Kansas-Oklahoma area in the United States.
Cosmically, there is 0. The cosmic abundance is comparable to those of cesiumpraseodymiumhafniumand tungsteneach of which is regarded as a reasonably scarce element. Although lead is not abundant, natural concentration processes have resulted in substantial deposits of commercial significance, particularly in the United States but also in Canada, AustraliaSpainGermany, Africa, and South America.
Significant deposits are found in the United States in the western states and the Mississippi valley. Rarely found free in nature, lead is present in several minerals, but all are of minor significance except the sulfidePbS galenaor lead glancewhich is the major source of lead production throughout the world.
Lead may be extracted by roasting the ore and then smelting it in a blast furnace or by direct smelting without roasting. Additional refining removes impurities present in the lead bullion produced by either process. Almost half of all refined lead is recovered from recycled scrap.
For commercial production, see lead processing. Uses of the metal Only a single crystalline modification, with a close-packed metallic lattice, is known. Properties that are responsible for the many uses of elemental lead include its ductilityease of welding, low melting pointhigh densityand ability to absorb gamma radiation and X-radiation.
Molten lead is an excellent solvent and collector for elemental silver and gold. The structural applications of lead are limited by its low tensile and fatigue strengths and its tendency to flow even when only lightly loaded.
When freshly cut, lead oxidizes quickly, forming a dull gray coating, formerly thought to be lead suboxide, Pb2 Obut now recognized as a mixture of lead and lead monoxide, PbO, which protects the metal from further corrosion.
Similarly, although lead is soluble in dilute nitric acidit is only superficially attacked by hydrochloric or sulfuric acids because the insoluble chloride PbCl2 or sulfate PbSO4 coatings that are formed prevent continued reaction. Because of this general chemical resistance, considerable amounts of lead are used in roofing, as coverings for electric cables placed in the ground or underwater, and as linings for water pipes and conduits and structures for the transportation and processing of corrosive substances.
The ease of oxidation of lead is enhanced by complex formation. The electrodeposition of lead is best effected from aqueous solutions containing lead hexafluorosilicate and hexafluorosilicic acid. Lead has many other applications, the largest of which is in the manufacture of storage batteries.
It is used in ammunition shot and bullets and as a constituent of solder, type metalbearing alloys, fusible alloys, and pewter.
In heavy and industrial machinery, sheets and other parts made from lead compounds may be used to dampen noise and vibration. Because lead effectively absorbs electromagnetic radiation of short wavelengths, it is used as a protective shielding around nuclear reactors, particle accelerators, X-ray equipment, and containers used for transporting and storing radioactive materials.
Together with the compound lead oxide PbO2 and with lead-antimony or lead-calcium alloys, it is employed in common storage batteries. Properties of the element Lead and its compounds are toxic and are retained by the body, accumulating over a long period of time—a phenomenon known as cumulative poisoning —until a lethal quantity is reached.
The toxicity of lead compounds increases as their solubility increases.Lead (Pb) Air Pollution. Contact Us. Share. As a result of EPA's regulatory efforts, levels of lead in the air decreased by 98 percent between and In , EPA significantly strengthened the air quality standards for lead to provide health protection for at-risk groups, especially children, and protect aquatic and terrestrial ecosystems.
Most other lead minerals are related to galena in some way; boulangerite, Pb 5 Sb 4 S 11, is a mixed sulfide derived from galena; anglesite, PbSO 4, is a product of galena oxidation; and cerussite or white lead ore, PbCO 3, is a decomposition product of leslutinsduphoenix.comciation: /ˈlɛd/ (LED).
lead (Pb), n a common soft, blue-gray, metallic element. Its atomic number is 82, and its atomic weight is In its metallic form, it is used as a protective shielding against radiographs.
(In dentistry, lead acts as a protective shield against the radiographic beam and is found in the lead apron and walls of the surrounding operatory.). Lead nitrate, 10 ug lead/kg bw, containing 10 u-Ci ()Pb/ug Pb was administered by gavage after a hr fast.
The ()Pb excreted in urine and feces was monitored for 96 hr. All monkeys were necropsied 96 hr after dosing, and the ()Pb contents of various tissues was determined. Lead damages the brain and the kidneys, it can cause anaemia and a form of gout with the doleful title of saturnine gout. Even the Romans knew about lead poisoning - the doctor Cornelius Celsus warned about the bad effects of lead white, used in paint and cosmetics, while the engineer Vitruvius recommended earthenware pipes over lead ones.
Lead is a chemical element with symbol Pb (from the Latin plumbum) and atomic number It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and has a relatively low melting leslutinsduphoenix.com freshly cut, lead is silvery with a hint of blue; it tarnishes to a dull gray color when exposed to air.
Lead has the highest atomic number of any stable element and three Pronunciation: /ˈlɛd/ (LED).