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Group-VI Transition Metal
Group 6, numbered by IUPAC style, is a group of elements in the periodic table. Its members are chromium (Cr), molybdenum (Mo), tungsten (W), and seaborgium (Sg). These are all transition metals and chromium, molybdenum and tungsten are refractory metals. The electron configuration of these elements do not follow a unified trend, though the outermost shells do correlate with trends in chemical behavior: "Group 6" is the new IUPAC name for this group; the old style name was "''group VIB''" in the old US system (CAS) or "''group VIA''" in the European system (old IUPAC). Group 6 must not be confused with the group with the old-style group crossed names of either ''VIA'' (US system, CAS) or ''VIB'' (European system, old IUPAC). ''That'' group is now called group 16. History Discoveries Chromium was first reported on July 26, 1761, when Johann Gottlob Lehmann found an orange-red mineral in the Beryozovskoye mines in the Ural Mountains of Russia, which he named "Siberian red ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Group 5 Element
Group 5 is a group of elements in the periodic table. Group 5 contains vanadium (V), niobium (Nb), tantalum (Ta) and dubnium (Db). This group lies in the d-block of the periodic table. This group is sometimes called the vanadium group or vanadium 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. As is typical for early transition metals, niobium and tantalum have only the group oxidation state of +5 as a major one, and are quite electropositive (it is easy to donate electrons) and have a less rich coordination chemistry (the chemistry of metallic ions bound with molecules). Due to the effects of the lanthanide contraction, the decrease in ionic radii in the lanthanides, they are very similar in properties. Vanadium is somewhat distinct due to its smaller size: it has well-defined +2, +3 and +4 states as well (although +5 is more stable). The lighter three Group 5 el ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refractory Metals
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 tem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron
Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's outer and inner core. It is the fourth most abundant element in the Earth's crust, being mainly deposited by meteorites in its metallic state. Extracting usable metal from iron ores requires kilns or furnaces capable of reaching , about 500 °C (900 °F) higher than that required to smelt copper. Humans started to master that process in Eurasia during the 2nd millennium BC and the use of iron tools and weapons began to displace copper alloys – in some regions, only around 1200 BC. That event is considered the transition from the Bronze Age to the Iron Age. In the modern world, iron alloys, such as steel, stainless steel, cast iron and special steels, are by far the most common industrial metals, due to their mechan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenium
Selenium is a chemical element; it has symbol (chemistry), symbol Se and atomic number 34. It has various physical appearances, including a brick-red powder, a vitreous black solid, and a grey metallic-looking form. It seldom occurs in this elemental state or as pure ore compounds in Earth's crust. Selenium ( ) was discovered in 1817 by , who noted the similarity of the new element to the previously discovered tellurium (named for the Earth). Selenium is found in :Sulfide minerals, metal sulfide ores, where it substitutes for sulfur. Commercially, selenium is produced as a byproduct in the refining of these ores. Minerals that are pure selenide or selenate compounds are rare. The chief commercial uses for selenium today are glassmaking and pigments. Selenium is a semiconductor and is used in photocells. Applications in electronics, once important, have been mostly replaced with silicon semiconductor devices. Selenium is still used in a few types of Direct current, DC power surge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead
Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleable, and also has a relatively low melting point. When freshly cut, lead is a shiny gray with a hint of blue. It tarnishes to a dull gray color when exposed to air. Lead has the highest atomic number of any stable nuclide, stable element and three of its isotopes are endpoints of major nuclear decay chains of heavier elements. Lead is a relatively unreactive post-transition metal. Its weak metallic character is illustrated by its Amphoterism, amphoteric nature; lead and lead oxides react with acids and base (chemistry), bases, and it tends to form covalent bonds. Lead compounds, Compounds of lead are usually found in the +2 oxidation state rather than the +4 state common with lighter members of the carbon group. Exceptions are mostly limited ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yellow
Yellow is the color between green and orange on the spectrum of light. It is evoked by light with a dominant wavelength of roughly 575585 nm. It is a primary color in subtractive color systems, used in painting or color printing. In the RGB color model, used to create colors on television and computer screens, yellow is a secondary color made by combining red and green at equal intensity. Carotenoids give the characteristic yellow color to autumn leaves, corn, canaries, daffodils, and lemons, as well as egg yolks, buttercups, and bananas. They absorb light energy and protect plants from photo damage in some cases. Sunlight has a slight yellowish hue when the Sun is near the horizon, due to atmospheric scattering of shorter wavelengths (green, blue, and violet). Because it was widely available, yellow ochre pigment was one of the first colors used in art; the Lascaux cave in France has a painting of a yellow horse 17,000 years old. Ochre and orpiment pigmen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Russia
Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders of Russia, land borders with fourteen countries. Russia is the List of European countries by population, most populous country in Europe and the List of countries and dependencies by population, ninth-most populous country in the world. It is a Urbanization by sovereign state, highly urbanised country, with sixteen of its urban areas having more than 1 million inhabitants. Moscow, the List of metropolitan areas in Europe, most populous metropolitan area in Europe, is the capital and List of cities and towns in Russia by population, largest city of Russia, while Saint Petersburg is its second-largest city and Society and culture in Saint Petersburg, cultural centre. Human settlement on the territory of modern Russia dates back to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ural Mountains
The Ural Mountains ( ),; , ; , or simply the Urals, are a mountain range in Eurasia that runs north–south mostly through Russia, from the coast of the Arctic Ocean to the river Ural (river), Ural and northwestern Kazakhstan.Ural Mountains , Encyclopædia Britannica on-line The mountain range forms part of the Boundaries between the continents of Earth, conventional boundary between the continents of Europe and Asia, marking the separation between European Russia and Siberia. Vaygach Island and the islands of Novaya Zemlya form a further continuation of the chain to the north into the Arctic Ocean. The average altitudes of the Urals are around , the highest point being Mount Narodnaya, which reaches a height of . The mountains lie within the Ural (region), Ural geographical region and significantl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beryozovskoye Deposit
Beryozovskoye deposit, Berezovskoe gold deposit, Berezovsky deposit, Berezovsk Mines, and some other names () is the first known to primary deposit of gold in Russia. It is located 13 km northwest of Yekaterinburg in the central Urals Federal District. It was discovered in 1745 by a ''raskolnik'' Yerofey Markov. Minerals of the Beryozovskoye gold ore deposit The first mine was established in 1747. The deposit is named after the Beryozovka River (a tributary of ) and is associated with the settlement of Berezovsky, now the town of [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johann Gottlob Lehmann (scientist)
Johann Gottlob Lehmann (4 August 171922 January 1767) was a German mineralogist and geologist noted for his work and research contributions to the geologic record leading to the development of stratigraphy. Life and career Lehmann was born in Langenhennersdorf, Electorate of Saxony and attended the University of Wittenberg, from which he received an M.D. in 1741, and then established a practice in Dresden. Living in Saxony, he developed an interest in the local mining industry, and published on the chemical composition of ore deposits. In 1750, the Royal Prussian Academy of Sciences commissioned him to study mining practices throughout Prussia. In 1761, the Russian Imperial Academy of Sciences invited him to Saint Petersburg, where he became professor of chemistry and director of the imperial museum there. At the Beryozovskoye deposit in the Urals he discovered a lead ore with a reddish-orange mineral (), which he named "Rotbleierz" (red lead ore); today in English its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cut Ruby
Cut or CUT may refer to: Common uses * The act of cutting, the separation of an object into two through acutely directed force ** A type of wound ** Cut (archaeology), a hole dug in the past ** Cut (clothing), the style or shape of a garment ** Cut (earthworks), an excavation to make way for a transport route ** Cut (gems) ** Cut of meat * Cut (etiquette), a snub or slight such as failure to greet an acquaintance Geography Romania * Cut, Alba, a commune * Cut, a village in Dumbrava Roșie United States * Cut, Texas, an unincorporated community * Cut River (Mackinac County, Michigan) * Cut River (Roscommon County, Michigan) * Custer County Airport, South Dakota, US (FAA identifier CUT) Computing and mathematics * Cut (logic programming) * cut (Unix), a command line utility * Cut, copy, and paste, a set of editing procedures * Control Unit Terminal, a kind of IBM display terminal for mainframe computers * Cut (graph theory) Books * ''Cut'' (manga), a 2008 Japanese manga * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Group 16 Element
The chalcogens (ore forming) ( ) are the chemical elements in group (periodic table), group 16 of the periodic table. This group is also known as the oxygen family. Group 16 consists of the elements oxygen (O), sulfur (S), selenium (Se), tellurium (Te), and the Radioactive decay, radioactive elements polonium (Po) and livermorium (Lv). Often, oxygen is treated separately from the other chalcogens, sometimes even excluded from the scope of the term "chalcogen" altogether, due to its very different chemical behavior from sulfur, selenium, tellurium, and polonium. The word "chalcogen" is derived from a combination of the Greek word () principally meaning copper (the term was also used for bronze, brass, any metal in the poetic sense, ore and coin), and the Latinized Greek word , meaning ''born'' or ''produced''. Sulfur has been known since antiquity, and oxygen was recognized as an element in the 18th century. Selenium, tellurium and polonium were discovered in the 19th century, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
