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The density of osmium is slightly greater than that of iridium; the two are so similar (22.587 versus 22.562 g/cm 3 at 20 °C) that each was at one time considered to be the densest element. Only in the 1990s were measurements made accurately enough (by means of X-ray crystallography) to be certain that osmium is the denser of the two. [11] [15]
Perey discovered it as a decay product of 227 Ac. [177] Francium was the last element to be discovered in nature, rather than synthesized in the lab, although four of the "synthetic" elements that were discovered later (plutonium, neptunium, astatine, and promethium) were eventually found in trace amounts in nature as well. [178]
Iron is a part of some hormones as well. A lack of iron in the body can cause iron deficiency anemia, and an excess of iron in the body can be toxic. [7] Some ruthenium-containing molecules may be used to fight cancer. [8] Normally, however, ruthenium plays no role in the human body. [3] Both osmium and hassium have no known biological roles ...
Its identification was based upon the bright-blue lines in its spectrum, and it was the first element discovered by spectrum analysis. Barium (Ba) 56 βαρύς (barys) Greek via Neo-Latin "heavy" βαρύς (barys) means "heavy". The oxide was initially called "barote", then "baryta", which was modified to "barium" to describe the metal.
Antoine-Laurent de Lavoisier (/ l ə ˈ v w ɑː z i eɪ / lə-VWAH-zee-ay; [1] [2] [3] French: [ɑ̃twan lɔʁɑ̃ də lavwazje]; 26 August 1743 – 8 May 1794), [4] also Antoine Lavoisier after the French Revolution, was a French nobleman and chemist who was central to the 18th-century chemical revolution and who had a large influence on both the history of chemistry and the history of biology.
He discovered that air is not a single substance and contains a life-giving substance – later called oxygen – 170 years before Scheele's discovery of the element. He correctly identified this "food of life" with the gas (also oxygen) given off by heating nitre ( saltpetre ). [ 1 ]
This is an accepted version of this page This is the latest accepted revision, reviewed on 17 November 2024. Development of the table of chemical elements The American chemist Glenn T. Seaborg —after whom the element seaborgium is named—standing in front of a periodic table, May 19, 1950 Part of a series on the Periodic table Periodic table forms 18-column 32-column Alternative and ...
Martin Heinrich Klaproth independently discovered the same oxide and called it ochroia. It took another 30 years for researchers to determine that other elements were contained in the two ores ceria and yttria (the similarity of the rare-earth metals' chemical properties made their separation difficult).