![]() ![]() The first clearly authentic report of the free substance was made in 1649 by Johann Schroeder, a German pharmacist, who prepared arsenic by heating its oxide with charcoal. It is not certain, however, that this natural scientist and scholar actually observed the free element. The element itself possibly was first observed in the 13th century by Albertus Magnus, who noted the appearance of a metal-like substance when arsenicum, another name for As 2S 3, was heated with soap. By the 11th century ce three species of “arsenic” were recognized: white (As 4 O 6), yellow (As 2S 3), and red (As 4S 4). Then, in the 1st century ce, the writers Pliny the Elder and Pedanius Dioscorides both described auripigmentum, a substance now thought to have been the dyestuff orpiment, As 2 S 3. In the 4th century bce Aristotle wrote of a substance called sandarache, now believed to have been the mineral realgar, a sulfide of arsenic. 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!Ĩ14 ☌ (1,497 ☏) at 36 atmospheres pressureġ s 22 s 22 p 63 s 23 p 63 d 104 s 24 p 3Īrsenic was known in the form of certain of its compounds long before it was clearly recognized as a chemical element.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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