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The blue plaque for Smithson Tennant in Finkle Street, Selby, North Yorkshire. Smithson Tennant FRS (30 November 1761 [1] – 22 February 1815 [2]) was an English chemist.He is best known for his discovery of the elements iridium and osmium, which he found in the residues from the solution of platinum ores in 1803.
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]
Tennant had been working on samples of South American platinum in parallel with Wollaston and discovered two new elements, which he named osmium and iridium, and published the iridium results in 1804. [115] Collet-Descotils also found iridium the same year, but not osmium. [85] 45 Rhodium: 1804 H. Wollaston: 1804 H. Wollaston
Osmium dioxide is another known oxide of osmium, which can be obtained by the reaction of osmium with a variety of oxidizing agents, including, sodium chlorate, osmium tetroxide, and nitric oxide at about 600 °C. [18] [19] It does not dissolve in water, but is attacked by dilute hydrochloric acid. [20] [21] The crystals have rutile structure. [22]
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 ...
Scheele made one other very important scientific discovery in 1774, arguably more revolutionary than his isolation of oxygen. He identified lime , silica , and iron in a specimen of pyrolusite (impure manganese dioxide) given to him by his friend, Johann Gottlieb Gahn , but could not identify an additional component (this was the manganese ...
Osmium oxide may refer to: Osmium dioxide, OsO 2; Osmium tetroxide, OsO 4 This page was last edited on 4 March 2021, at 20:47 (UTC). Text is available under the ...
It is also known as red iron oxide, especially when used in pigments. It is one of the three main oxides of iron , the other two being iron(II) oxide (FeO), which is rare; and iron(II,III) oxide ( Fe 3 O 4 ), which also occurs naturally as the mineral magnetite .