page_title: Lead
section_title: Applications
hierarchical_section_title: Lead / Applications
caption_attribution_description: Lead bricks being used to shield a radioactive sample (Cs-137). Taken by L. Chang, 3-17-2004.
context_page_description: Lead is a chemical element with the symbol Pb and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When 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 of its isotopes are endpoints of major nuclear decay chains of heavier elements.
  Lead is a relatively unreactive post-transition metal. Its weak metallic character is illustrated by its amphoteric nature; lead and lead oxides react with acids and bases, and it tends to form covalent bonds. Compounds of lead are usually found in the +2 oxidation state rather than the +4 state common with lighter members of the carbon group. Exceptions are mostly limited to organolead compounds. Like the lighter members of the group, lead tends to bond with itself; it can form chains and polyhedral structures.
  Lead is easily extracted from its ores; prehistoric people in Western Asia knew of it. Galena is a principal ore of lead which often bears silver.
context_section_description: Contrary to popular belief, pencil leads in wooden pencils have never been made from lead. When the pencil originated as a wrapped graphite writing tool, the particular type of graphite used was named plumbago (literally, act for lead or lead mockup).
caption: Bricks of lead (alloyed with 4% antimony) are used as radiation shielding.[200]
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