Rhenium in the context of Manganese

Troy weight is a system of units of mass whose origin is uncertain. By far the most common troy unit is the troy ounce (oz t), the standard mass unit for precious metals in industry and in trade; it equals 31.1034768 grams. The troy weight units are the grain, the pennyweight (24 grains), the troy ounce (20 pennyweights), and the troy pound (12 troy ounces). The troy grain is equal to the grain unit of the avoirdupois and apothecaries' systems, but the troy ounce is heavier than the avoirdupois ounce, and the troy pound is lighter than the avoirdupois pound.

Precious metals are rare, naturally occurring metallic chemical elements of high economic value. Precious metals, particularly the noble metals, are more corrosion resistant and less chemically reactive than most elements. They are usually ductile and have a high lustre. Historically, precious metals were important as currency but they are now regarded mainly as investment and industrial raw materials. Gold, silver, platinum, and palladium each have an ISO 4217 currency code.

The best known precious metals are the precious coinage metals, which are gold and silver. Although both have industrial uses, they are better known for their uses in art, jewelry, and coinage. Other precious metals include the platinum group metals: ruthenium, rhodium, palladium, osmium, iridium, and platinum, of which platinum is the most widely traded.The demand for precious metals is driven not only by their practical use but also by their role as investments and a store of value. Historically, precious metals have commanded much higher prices than common industrial metals.

A native metal is any metal that is found pure in its metallic form in nature. Metals that can be found as native deposits singly or in alloys include antimony, arsenic, bismuth, cadmium, chromium, cobalt, indium, iron, manganese, molybdenum, nickel, niobium, rhenium, tantalum, tellurium, tin, titanium, tungsten, vanadium, and zinc, as well as the gold group (gold, copper, lead, aluminium, mercury, silver) and the platinum group (platinum, iridium, osmium, palladium, rhodium, ruthenium). Among the alloys found in native state have been brass, bronze, pewter, German silver, osmiridium, electrum, white gold, silver-mercury amalgam, and gold-mercury amalgam.

Only gold, silver, copper and the platinum group occur native in large amounts. Over geological time scales, very few metals can resist natural weathering processes like oxidation, so mainly the less reactive metals such as gold and platinum are found as native metals. The others usually occur as isolated pockets where a natural chemical process reduces a common compound or ore of the metal, leaving the pure metal behind as small flakes or inclusions.

A noble metal is a metallic chemical element that is resistant to corrosion and is usually found in nature in its raw form. Gold, platinum, and the other platinum group metals (ruthenium, rhodium, palladium, osmium, iridium) are most often so classified. Silver, copper, and mercury are sometimes included as noble metals, but each of these usually occurs in nature combined with sulfur.

In more specialized fields of study and applications, the number of elements counted as noble metals can vary. In some contexts, the term is used only for copper, silver, and gold which have filled d-bands. In others, it is applied more broadly to any metallic or semimetallic element that does not react with a weak acid and give off hydrogen gas in the process. This broader set includes copper, mercury, technetium, rhenium, arsenic, antimony, bismuth, polonium, gold, the six platinum group metals, and silver.

The top quark, sometimes also referred to as the truth quark, (symbol: t) is the most massive of all observed elementary particles. It derives its mass from its coupling to the Higgs field. This coupling y_t is very close to unity; in the Standard Model of particle physics, it is the largest (strongest) coupling at the scale of the weak interactions and above. The top quark was discovered in 1995 by the CDF and DØ experiments at Fermilab.

Like all other quarks, the top quark is a fermion with spin-1/2 and participates in all four fundamental interactions: gravitation, electromagnetism, weak interactions, and strong interactions. It has an electric charge of +⁠ 2 /3⁠ e. It has a mass of 172.76±0.3 GeV/c, which is close to the rhenium atom mass (more precisely, the average of its isotopes). The antiparticle of the top quark is the top antiquark (symbol: t, sometimes called antitop quark or simply antitop), which differs from it only in that some of its properties have equal magnitude but opposite sign.

Refractory metals are a class of metals that are extraordinarily resistant to heat and wear. The expression is mostly used in the context of materials science, metallurgy and engineering. The definitions of which elements belong to this group differ. The most common definition includes five elements: two of the fifth period (niobium and molybdenum) and three of the sixth period (tantalum, tungsten, and rhenium). They all share some properties, including a melting point above 2000 °C and high hardness at room temperature. They are chemically inert and have a relatively high density. Their high melting points make powder metallurgy the method of choice for fabricating components from these metals. Some of their applications include tools to work metals at high temperatures, wire filaments, casting molds, and chemical reaction vessels in corrosive environments. Partly due to their high melting points, refractory metals are stable against creep deformation to very high temperatures.

Hydrodesulfurization (HDS), also called hydrotreatment or hydrotreating, is a catalytic chemical process widely used to remove sulfur (S) from natural gas and from refined petroleum products, such as gasoline or petrol, jet fuel, kerosene, diesel fuel, and fuel oils. The purpose of removing the sulfur, and creating products such as ultra-low-sulfur diesel, is to reduce the sulfur dioxide (SO₂) emissions that result from using those fuels in automotive vehicles, aircraft, railroad locomotives, ships, gas or oil burning power plants, residential and industrial furnaces, and other forms of fuel combustion.

Another important reason for removing sulfur from the naphtha streams within a petroleum refinery is that sulfur, even in extremely low concentrations, poisons the noble metal catalysts (platinum and rhenium) in the catalytic reforming units that are subsequently used to upgrade the octane rating of the naphtha streams.

Technetium is a chemical element; it has symbol Tc and atomic number 43. It is the lightest element whose isotopes are all radioactive. Technetium and promethium are the only radioactive elements whose neighbours in the sense of atomic number are both stable. All available technetium is produced as a synthetic element. Naturally occurring technetium is a spontaneous fission product in uranium ore and thorium ore (the most common source), or the product of neutron capture in molybdenum ores. This silvery gray, crystalline transition metal lies between manganese and rhenium in group 7 of the periodic table, and its chemical properties are intermediate between those of both adjacent elements. The most common naturally occurring isotope is Tc, in traces only.

Many of technetium's properties had been predicted by Dmitri Mendeleev before it was discovered; Mendeleev noted a gap in his periodic table and gave the undiscovered element the provisional name ekamanganese (Em). In 1937, technetium became the first predominantly artificial element to be produced, hence its name (from the Greek technetos, 'artificial', + -ium).

A mononuclidic element or monotopic element is one of the 21 chemical elements that is found naturally on Earth essentially as a single nuclide (which may, or may not, be a stable nuclide). This single nuclide will have a characteristic atomic mass. Thus, the element's natural isotopic abundance is dominated by one isotope that is either stable or very long-lived. There are 19 elements in the first category (which are both monoisotopic and mononuclidic), and 2 (bismuth and protactinium) in the second category (mononuclidic but not monoisotopic, since they have zero, not one, stable nuclides). A list of the 21 mononuclidic elements is given at the end of this article.

Of the 26 monoisotopic elements that, by definition, have only one stable isotope, seven are not considered mononuclidic, due to the presence of a significant fraction of a very long-lived (primordial) radioisotope. These elements are vanadium, rubidium, indium, lanthanum, europium, lutetium, and rhenium.

Group 7, numbered by IUPAC nomenclature, is a group of elements in the periodic table. It contains manganese (Mn), technetium (Tc), rhenium (Re) and bohrium (Bh). This group lies in the d-block of the periodic table, and are hence transition metals. This group is sometimes called the manganese group or manganese family after its lightest member; however, the group itself has not acquired a trivial name because it belongs to the broader grouping of the transition metals.

The group 7 elements tend to have a major group oxidation state (+7), although this trend is markedly less coherent than the previous groups. Like other groups, the members of this family show patterns in their electron configurations, especially the outermost shells resulting in trends in chemical behavior. In nature, manganese is a fairly common element, whereas rhenium is rare, technetium only occurs in trace quantities, and bohrium is entirely synthetic.

Masataka Ogawa (小川 正孝, Ogawa Masataka; 21 February 1865 – 11 July 1930) was a Japanese chemist mainly known for the claimed discovery of element 43 (later known as technetium), which he named nipponium. In fact, he had discovered, but misidentified, element 75 (later called rhenium).

After graduating from the University of Tokyo, he studied under William Ramsay in London, where he worked on the analysis of the rare mineral thorianite. He extracted and isolated a small amount of an apparently unknown substance from the mineral, which he announced as the discovery of element 43, naming the newly discovered element nipponium. He published his results in 1909 and a notice was also published in the Journal of the American Chemical Society. For this work, he was awarded a doctorate and the highest prize of the Tokyo Chemical Society. However, no other researchers were able to replicate his discovery, and the announcement was forgotten.

Walter Noddack (17 August 1893 – 7 December 1960) was a German chemist. He, Ida Tacke (who later married Noddack), and Otto Berg reported the discovery of element 43 and element 75 in 1925.

Ida Noddack (25 February 1896 – 24 September 1978), née Tacke, was a German chemist and physicist. In 1934 she was the first to mention the idea later named nuclear fission. With her husband Walter Noddack, and Otto Berg, she discovered element 75, rhenium. She was nominated three times for the Nobel Prize in Chemistry.

Otto Berg (23 November 1874 – 1939) was a German scientist. He is one of the scientists credited with discovering rhenium, the last element to be discovered having a stable isotope.