The periodic table is made up of 118 elements. As a catalyst, platinum has many applications, notably in automotive catalytic converters and in petroleum refining. The electrical resistivity of platinum is relatively high and depends markedly upon the temperature the International Temperature Scale from −259.35 to 961.78 ☌ (−434.83 to 1,763.2 ☏)is defined in terms of a resistance thermometer made with platinum wire. The prototype international standard kilogram of mass was made from an alloy of 90 percent platinum and 10 percent iridium. Jewelry and dental alloys account for much of its use platinum-iridium is used for surgical pins. Platinum is used for electrical contacts and sparking points because it resists both the high temperatures and chemical attack of electric arcs. Platinum, one of the most abundant platinum metals, and its alloys are indispensable in the chemical laboratory for electrodes and for crucibles and dishes in which materials can be heated to high temperatures. (It does dissolve slowly in hydrochloric acid in the presence of air.) Small amounts of iridium are commonly added to give a harder, stronger alloy that retains the advantages of pure platinum. For example, its surface remains bright after being brought to white heat in air, and, though it readily dissolves in aqua regia, it is scarcely attacked by simple acids. A very heavy, precious, silver-white metal, platinum is soft and ductile and has a high melting point and good resistance to corrosion and chemical attack. Platinum (Pt), chemical element, the best known and most widely used of the six platinum metals of Groups 8–10, Periods 5 and 6, of the periodic table. SpaceNext50 Britannica presents SpaceNext50, From the race to the Moon to space stewardship, we explore a wide range of subjects that feed our curiosity about space!.Learn about the major environmental problems facing our planet and what can be done about them! Saving Earth Britannica Presents Earth’s To-Do List for the 21st Century.Britannica Beyond We’ve created a new place where questions are at the center of learning.100 Women Britannica celebrates the centennial of the Nineteenth Amendment, highlighting suffragists and history-making politicians.COVID-19 Portal While this global health crisis continues to evolve, it can be useful to look to past pandemics to better understand how to respond today.Student Portal Britannica is the ultimate student resource for key school subjects like history, government, literature, and more.This Time in History In these videos, find out what happened this month (or any month!) in history.#WTFact Videos In #WTFact Britannica shares some of the most bizarre facts we can find.Demystified Videos In Demystified, Britannica has all the answers to your burning questions.Britannica Explains In these videos, Britannica explains a variety of topics and answers frequently asked questions.Britannica Classics Check out these retro videos from Encyclopedia Britannica’s archives.
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