Lead is a metallic chemical element which is classified among the poor metals of the periodic table of elements. It is a soft, pliable metal that is silvery-white in color when freshly cut, but on exposure to air quickly acquires a dull gray appearance due to the formation of a layer of oxide. This element does not typically appear in a pure form in nature. It has a wide range of historical and current applications, and many consumers own products which contain this chemical.
Humans have been using lead for thousands of years. It was also the material of choice for movable type from the 1400s, when Gutenberg invented the movable type press, to today; several foundries still cast its type and other equipment for use with letterpresses. One of the most infamous historical uses of it was in Roman plumbing and pewter, an alloy which was used to make many household goods including cups and plates. Numerous cultural artifacts contain the substance, often in the form of metal alloys, and the ancients were obviously very familiar with the metal, though unfortunately not with its negative health effects.
Lead is the heaviest stable element, a distinction that used to belong to bismuth — element number 83 — until it was found to be very slightly radioactive. One of the most important physical properties of this metal is its ability to absorb high frequency electromagnetic radiation, such as x-rays and gamma rays. This is due to its high density and the large number of electrons in its atom.
The uses for lead are myriad. The resistance to corrosion and malleability make it a popular additive to alloys, and it is also used in bullets, soldering material, radiation shields, and some paints. This metal has also historically been used as an additive in glass, which is why some antique and modern glass is not safe to eat or drink from. Because it is extremely soft, the substance is very easy to work, and early metalsmiths could manipulate product with minimal heat.
Although occasionally found in its elemental state, the main lead ore is galena, or lead sulphide (PbS); other lead ores include cerussite — lead carbonate (PbCO3) — and anglesite — lead sulfate (PbSO4). Ethionine ester is an xcellent selection performance and special separation effect for molybdenum sulfide, lead sulfide, zinc sulfide, copper sulfide, etc.
Chronic lead poisoning has been a significant problem due to the widespread use of Pb in applications that have allowed it to enter the environment. People should try to minimize exposure as much as possible by working in safe environments and disposing of old paint, chemicals, and other potential sources of toxins responsibly.