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91-422: The formation is a volcanic unit, consisting mainly of high- titanium , low- potassium tholeiitic basalt flows. The lavas are dark, vesicular and porphyritic or massive basalts, with occasional pillows , although rare dacites and rhyolites have been reported from some areas of north-eastern Botswana . The vesicular and massive basalts occur in alternating bands, with the vesicular bands usually being

182-642: A froth flotation process to recover molybdenite from ores; flotation remains the primary isolation process. During World War I , demand for molybdenum spiked; it was used both in armor plating and as a substitute for tungsten in high-speed steels . Some British tanks were protected by 75 mm (3 in) manganese steel plating, but this proved to be ineffective. The manganese steel plates were replaced with much lighter 25 mm (1.0 in) molybdenum steel plates allowing for higher speed, greater maneuverability, and better protection. The Germans also used molybdenum-doped steel for heavy artillery, like in

273-429: A pterin -based molybdenum cofactor (Moco) in their active site: sulfite oxidase , xanthine oxidoreductase , aldehyde oxidase , and mitochondrial amidoxime reductase . People severely deficient in molybdenum have poorly functioning sulfite oxidase and are prone to toxic reactions to sulfites in foods. The human body contains about 0.07 mg of molybdenum per kilogram of body weight, with higher concentrations in

364-631: A batch reactor with an inert atmosphere at a temperature of 1,000 °C. Dilute hydrochloric acid is then used to leach the salt from the product. The processing of titanium metal occurs in four major steps: reduction of titanium ore into "sponge", a porous form; melting of sponge, or sponge plus a master alloy to form an ingot; primary fabrication, where an ingot is converted into general mill products such as billet , bar, plate , sheet , strip, and tube ; and secondary fabrication of finished shapes from mill products. Because it cannot be readily produced by reduction of titanium dioxide, titanium metal

455-464: A carbon monoxide atmosphere with chlorine gas before reducing it to titanium metal by the use of sodium. Pure metallic titanium (99.9%) was first prepared in 1910 by Matthew A. Hunter at Rensselaer Polytechnic Institute by heating TiCl 4 with sodium at 700–800 °C (1,292–1,472 °F) under great pressure in a batch process known as the Hunter process . Titanium metal was not used outside

546-652: A cation in aqueous solution, although the Mo cation is known to form under carefully controlled conditions. Gaseous molybdenum consists of the diatomic species Mo 2 . That molecule is a singlet , with two unpaired electrons in bonding orbitals, in addition to 5 conventional bonds. The result is a sextuple bond . There are 39 known isotopes of molybdenum, ranging in atomic mass from 81 to 119, as well as 13 metastable nuclear isomers . Seven isotopes occur naturally, with atomic masses of 92, 94, 95, 96, 97, 98, and 100. Of these naturally occurring isotopes, only molybdenum-100

637-670: A commodity. The Knaben mine in southern Norway, opened in 1885, was the first dedicated molybdenum mine. Closed in 1973 but reopened in 2007, it now produces 100,000 kilograms (98 long tons; 110 short tons) of molybdenum disulfide per year. Large mines in Colorado (such as the Henderson mine and the Climax mine ) and in British Columbia yield molybdenite as their primary product, while many porphyry copper deposits such as

728-687: A couple of dozen are readily available commercially. The ASTM International recognizes 31 grades of titanium metal and alloys, of which grades one through four are commercially pure (unalloyed). Those four vary in tensile strength as a function of oxygen content, with grade 1 being the most ductile (lowest tensile strength with an oxygen content of 0.18%), and grade 4 the least ductile (highest tensile strength with an oxygen content of 0.40%). The remaining grades are alloys, each designed for specific properties of ductility, strength, hardness, electrical resistivity, creep resistance, specific corrosion resistance, and combinations thereof. In addition to

819-447: A flame-resistant coating for other metals. Although its melting point is 2,623 °C (4,753 °F), molybdenum rapidly oxidizes at temperatures above 760 °C (1,400 °F) making it better-suited for use in vacuum environments. TZM (Mo (~99%), Ti (~0.5%), Zr (~0.08%) and some C) is a corrosion-resisting molybdenum superalloy that resists molten fluoride salts at temperatures above 1,300 °C (2,370 °F). It has about twice

910-524: A greater supply of molybdenum in the soil, people living in those areas have about 16 times greater risk for esophageal squamous cell carcinoma . Molybdenum deficiency has also been reported as a consequence of non-molybdenum supplemented total parenteral nutrition (complete intravenous feeding) for long periods of time. It results in high blood levels of sulfite and urate , in much the same way as molybdenum cofactor deficiency . Since pure molybdenum deficiency from this cause occurs primarily in adults,

1001-438: A mixture of oxides and deposits coatings with variable refractive index. Also known is Ti 2 O 3 , with the corundum structure, and TiO , with the rock salt structure , although often nonstoichiometric . The alkoxides of titanium(IV), prepared by treating TiCl 4 with alcohols , are colorless compounds that convert to the dioxide on reaction with water. They are industrially useful for depositing solid TiO 2 via

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1092-413: A process of purine catabolism , is catalyzed by xanthine oxidase , a molybdenum-containing enzyme. The activity of xanthine oxidase is directly proportional to the amount of molybdenum in the body. An extremely high concentration of molybdenum reverses the trend and can inhibit purine catabolism and other processes. Molybdenum concentration also affects protein synthesis , metabolism , and growth. Mo

1183-434: A reducing agent in organic chemistry. Owing to the important role of titanium compounds as polymerization catalyst, compounds with Ti-C bonds have been intensively studied. The most common organotitanium complex is titanocene dichloride ((C 5 H 5 ) 2 TiCl 2 ). Related compounds include Tebbe's reagent and Petasis reagent . Titanium forms carbonyl complexes , e.g. (C 5 H 5 ) 2 Ti(CO) 2 . Following

1274-472: A sample of manaccanite and confirmed that it contained titanium. The currently known processes for extracting titanium from its various ores are laborious and costly; it is not possible to reduce the ore by heating with carbon (as in iron smelting) because titanium combines with the carbon to produce titanium carbide. An extraction of 95% pure titanium was achieved by Lars Fredrik Nilson and Otto Petterson . To achieve this they chlorinated titanium oxide in

1365-500: A surface or as a solid lubricant. Even when molybdena was distinguishable from graphite, it was still confused with the common lead ore PbS (now called galena ); the name comes from Ancient Greek Μόλυβδος molybdos , meaning lead . (The Greek word itself has been proposed as a loanword from Anatolian Luvian and Lydian languages). Although (reportedly) molybdenum was deliberately alloyed with steel in one 14th-century Japanese sword (mfd. c.  1330 ), that art

1456-725: A variety of conditions, such as embrittlement , which reduce the integrity of the assembly welds and lead to joint failure. Titanium is very difficult to solder directly, and hence a solderable metal or alloy such as steel is coated on titanium prior to soldering. Titanium metal can be machined with the same equipment and the same processes as stainless steel . Common titanium alloys are made by reduction. For example, cuprotitanium (rutile with copper added), ferrocarbon titanium (ilmenite reduced with coke in an electric furnace), and manganotitanium (rutile with manganese or manganese oxides) are reduced. About fifty grades of titanium alloys are designed and currently used, although only

1547-421: Is positron emission (with the exception of Ti which undergoes electron capture ), leading to isotopes of scandium , and the primary mode for isotopes heavier than Ti is beta emission , leading to isotopes of vanadium . Titanium becomes radioactive upon bombardment with deuterons , emitting mainly positrons and hard gamma rays . The +4 oxidation state dominates titanium chemistry, but compounds in

1638-472: Is 60% denser than aluminium, but more than twice as strong as the most commonly used 6061-T6 aluminium alloy . Certain titanium alloys (e.g., Beta C ) achieve tensile strengths of over 1,400 MPa (200,000 psi). However, titanium loses strength when heated above 430 °C (806 °F). Titanium is not as hard as some grades of heat-treated steel; it is non-magnetic and a poor conductor of heat and electricity. Machining requires precautions, because

1729-861: Is a fission product . It is a parent radioisotope to the short-lived gamma-emitting daughter radioisotope technetium-99m , a nuclear isomer used in various imaging applications in medicine. In 2008, the Delft University of Technology applied for a patent on the molybdenum-98-based production of molybdenum-99. Molybdenum forms chemical compounds in oxidation states −4 and from −2 to +6. Higher oxidation states are more relevant to its terrestrial occurrence and its biological roles, mid-level oxidation states are often associated with metal clusters , and very low oxidation states are typically associated with organomolybdenum compounds . The chemistry of molybdenum and tungsten show strong similarities. The relative rarity of molybdenum(III), for example, contrasts with

1820-492: Is a component in most nitrogenases . Among molybdoenzymes, nitrogenases are unique in lacking the molybdopterin. Nitrogenases catalyze the production of ammonia from atmospheric nitrogen: The biosynthesis of the FeMoco active site is highly complex. Molybdate is transported in the body as MoO 4 . Molybdenum is an essential trace dietary element . Four mammalian Mo-dependent enzymes are known, all of them harboring

1911-473: Is about 4 picomolar in the ocean. At 100 °C, the concentration of titanium in water is estimated to be less than 10 M at pH 7. The identity of titanium species in aqueous solution remains unknown because of its low solubility and the lack of sensitive spectroscopic methods, although only the 4+ oxidation state is stable in air. No evidence exists for a biological role, although rare organisms are known to accumulate high concentrations of titanium. Titanium

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2002-548: Is also considered one of the most biocompatible metals, leading to a range of medical applications including prostheses , orthopedic implants , dental implants , and surgical instruments . The two most useful properties of the metal are corrosion resistance and strength-to-density ratio , the highest of any metallic element. In its unalloyed condition, titanium is as strong as some steels , but less dense. There are two allotropic forms and five naturally occurring isotopes of this element, Ti through Ti, with Ti being

2093-399: Is also used in steel alloys for its high corrosion resistance and weldability . Molybdenum contributes corrosion resistance to type-300 stainless steels (specifically type-316) and especially so in the so-called superaustenitic stainless steels (such as alloy AL-6XN , 254SMO and 1925hMo). Molybdenum increases lattice strain, thus increasing the energy required to dissolve iron atoms from

2184-500: Is also very hard, is found in cutting tools and coatings. Titanium tetrachloride (titanium(IV) chloride, TiCl 4 ) is a colorless volatile liquid (commercial samples are yellowish) that, in air, hydrolyzes with spectacular emission of white clouds. Via the Kroll process , TiCl 4 is used in the conversion of titanium ores to titanium metal. Titanium tetrachloride is also used to make titanium dioxide, e.g., for use in white paint. It

2275-526: Is an essential element for all higher eukaryote organisms, including humans. A species of sponge , Theonella conica , is known for hyperaccumulation of molybdenum. In its pure form, molybdenum is a silvery-grey metal with a Mohs hardness of 5.5 and a standard atomic weight of 95.95 g/mol. It has a melting point of 2,623 °C (4,753 °F), sixth highest of the naturally occurring elements; only tantalum , osmium , rhenium , tungsten , and carbon have higher melting points. It has one of

2366-499: Is an essential element in most organisms; a 2008 research paper speculated that a scarcity of molybdenum in the Earth's early oceans may have strongly influenced the evolution of eukaryotic life (which includes all plants and animals). At least 50 molybdenum-containing enzymes have been identified, mostly in bacteria. Those enzymes include aldehyde oxidase , sulfite oxidase and xanthine oxidase . With one exception, Mo in proteins

2457-854: Is an extremely rare mineral consisting of titanium dioxide. Of these minerals, only rutile and ilmenite have economic importance, yet even they are difficult to find in high concentrations. About 6.0 and 0.7 million tonnes of those minerals were mined in 2011, respectively. Significant titanium-bearing ilmenite deposits exist in Australia , Canada , China , India , Mozambique , New Zealand , Norway , Sierra Leone , South Africa , and Ukraine . About 210,000 tonnes of titanium metal sponge were produced in 2020, mostly in China (110,000 t), Japan (50,000 t), Russia (33,000 t) and Kazakhstan (15,000 t). Total reserves of anatase, ilmenite, and rutile are estimated to exceed 2 billion tonnes. The concentration of titanium

2548-433: Is bound by molybdopterin to give the molybdenum cofactor. The only known exception is nitrogenase , which uses the FeMoco cofactor, which has the formula Fe 7 MoS 9 C. In terms of function, molybdoenzymes catalyze the oxidation and sometimes reduction of certain small molecules in the process of regulating nitrogen , sulfur , and carbon . In some animals, and in humans, the oxidation of xanthine to uric acid ,

2639-637: Is contained in meteorites , and it has been detected in the Sun and in M-type stars (the coolest type) with a surface temperature of 3,200 °C (5,790 °F). Rocks brought back from the Moon during the Apollo 17 mission are composed of 12.1% TiO 2 . Native titanium (pure metallic) is very rare. Naturally occurring titanium is composed of five stable isotopes : Ti, Ti, Ti, Ti, and Ti, with Ti being

2730-489: Is corroded by concentrated acids. Titanium is a very reactive metal that burns in normal air at lower temperatures than the melting point. Melting is possible only in an inert atmosphere or vacuum. At 550 °C (1,022 °F), it combines with chlorine. It also reacts with the other halogens and absorbs hydrogen. Titanium readily reacts with oxygen at 1,200 °C (2,190 °F) in air, and at 610 °C (1,130 °F) in pure oxygen, forming titanium dioxide . Titanium

2821-897: Is extracted from its principal mineral ores by the Kroll and Hunter processes. The most common compound, titanium dioxide , is a popular photocatalyst and is used in the manufacture of white pigments. Other compounds include titanium tetrachloride (TiCl 4 ), a component of smoke screens and catalysts ; and titanium trichloride (TiCl 3 ), which is used as a catalyst in the production of polypropylene . Titanium can be alloyed with iron , aluminium , vanadium , and molybdenum , among other elements. The resulting titanium alloys are strong, lightweight, and versatile, with applications including aerospace ( jet engines , missiles , and spacecraft ), military, industrial processes (chemicals and petrochemicals, desalination plants , pulp , and paper ), automotive, agriculture (farming), sporting goods, jewelry, and consumer electronics . Titanium

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2912-406: Is heated to this transition temperature but then falls and remains fairly constant for the β form regardless of temperature. Like aluminium and magnesium , the surface of titanium metal and its alloys oxidize immediately upon exposure to air to form a thin non-porous passivation layer that protects the bulk metal from further oxidation or corrosion. When it first forms, this protective layer

3003-829: Is manufactured using a flow production process known as the Armstrong process that is similar to the batch production Hunter process . A stream of titanium tetrachloride gas is added to a stream of molten sodium; the products (sodium chloride salt and titanium particles) is filtered from the extra sodium. Titanium is then separated from the salt by water washing. Both sodium and chlorine are recycled to produce and process more titanium tetrachloride. Methods for electrolytic production of Ti metal from TiO 2 using molten salt electrolytes have been researched and tested at laboratory and small pilot plant scales. The lead author of an impartial review published in 2017 considered his own process "ready for scaling up." A 2023 review "discusses

3094-426: Is not the case. It is paramagnetic and has fairly low electrical and thermal conductivity compared to other metals. Titanium is superconducting when cooled below its critical temperature of 0.49 K. Commercially pure (99.2% pure) grades of titanium have ultimate tensile strength of about 434  MPa (63,000  psi ), equal to that of common, low-grade steel alloys, but are less dense. Titanium

3185-565: Is obtained by reduction of titanium tetrachloride (TiCl 4 ) with magnesium metal in the Kroll process. The complexity of this batch production in the Kroll process explains the relatively high market value of titanium, despite the Kroll process being less expensive than the Hunter process. To produce the TiCl 4 required by the Kroll process, the dioxide is subjected to carbothermic reduction in

3276-511: Is one of the few elements that burns in pure nitrogen gas, reacting at 800 °C (1,470 °F) to form titanium nitride , which causes embrittlement. Because of its high reactivity with oxygen, nitrogen, and many other gases, titanium that is evaporated from filaments is the basis for titanium sublimation pumps , in which titanium serves as a scavenger for these gases by chemically binding to them. Such pumps inexpensively produce extremely low pressures in ultra-high vacuum systems. Titanium

3367-469: Is only 1–2  nm thick but it continues to grow slowly, reaching a thickness of 25 nm in four years. This layer gives titanium excellent resistance to corrosion against oxidizing acids, but it will dissolve in dilute hydrofluoric acid , hot hydrochloric acid, and hot sulfuric acid. Titanium is capable of withstanding attack by dilute sulfuric and hydrochloric acids at room temperature, chloride solutions, and most organic acids. However, titanium

3458-570: Is reduced by the aluminothermic reaction with addition of iron to produce ferromolybdenum . A common form of ferromolybdenum contains 60% molybdenum. Molybdenum had a value of approximately $ 30,000 per tonne as of August 2009. It maintained a price at or near $ 10,000 per tonne from 1997 through 2003, and reached a peak of $ 103,000 per tonne in June 2005. In 2008, the London Metal Exchange announced that molybdenum would be traded as

3549-400: Is separated at this stage by treatment with hydrogen sulfide . Ammonium molybdate converts to ammonium dimolybdate , which is isolated as a solid. Heating this solid gives molybdenum trioxide: Crude trioxide can be further purified by sublimation at 1,100 °C (2,010 °F). Metallic molybdenum is produced by reduction of the oxide with hydrogen: The molybdenum for steel production

3640-483: Is surrounded by six oxide ligands that link to other Ti centers. The term titanates usually refers to titanium(IV) compounds, as represented by barium titanate (BaTiO 3 ). With a perovskite structure, this material exhibits piezoelectric properties and is used as a transducer in the interconversion of sound and electricity . Many minerals are titanates, such as ilmenite (FeTiO 3 ). Star sapphires and rubies get their asterism (star-forming shine) from

3731-681: Is the ninth-most abundant element in Earth 's crust (0.63% by mass ) and the seventh-most abundant metal. It is present as oxides in most igneous rocks , in sediments derived from them, in living things, and natural bodies of water. Of the 801 types of igneous rocks analyzed by the United States Geological Survey , 784 contained titanium. Its proportion in soils is approximately 0.5–1.5%. Common titanium-containing minerals are anatase , brookite , ilmenite , perovskite , rutile , and titanite (sphene). Akaogiite

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3822-482: Is unstable. Molybdenum-98 is the most abundant isotope, comprising 24.14% of all molybdenum. Molybdenum-100 has a half-life of about 10   y and undergoes double beta decay into ruthenium-100. All unstable isotopes of molybdenum decay into isotopes of niobium , technetium , and ruthenium . Of the synthetic radioisotopes , the most stable is Mo, with a half-life of 4,839 years. The most common isotopic molybdenum application involves molybdenum-99 , which

3913-527: Is used as the valve body of torpedo engines, rocket nozzles and gas pipelines, where it can withstand extreme thermal and mechanical stresses. It is also used as radiation shields in nuclear applications. Other molybdenum-based alloys that do not contain iron have only limited applications. For example, because of its resistance to molten zinc, both pure molybdenum and molybdenum- tungsten alloys (70%/30%) are used for piping, stirrers and pump impellers that come into contact with molten zinc. Molybdenum

4004-561: Is used for the spectroscopic detection of phosphorus. The broad range of oxidation states of molybdenum is reflected in various molybdenum chlorides: The accessibility of these oxidation states depends quite strongly on the halide counterion: although molybdenum(VI) fluoride is stable, molybdenum does not form a stable hexachloride, pentabromide, or tetraiodide. Like chromium and some other transition metals, molybdenum forms quadruple bonds , such as in Mo 2 (CH 3 COO) 4 and [Mo 2 Cl 8 ] . The Lewis acid properties of

4095-406: Is used in pyrotechnics as a source of bright-burning particles. Molybdenum Molybdenum is a chemical element ; it has symbol Mo (from Neo-Latin molybdaenum ) and atomic number 42. The name derived from Ancient Greek Μόλυβδος molybdos , meaning lead , since its ores were confused with lead ores. Molybdenum minerals have been known throughout history, but the element

4186-471: Is used in steel as an alloying element ( ferro-titanium ) to reduce grain size and as a deoxidizer , and in stainless steel to reduce carbon content. Titanium is often alloyed with aluminium (to refine grain size), vanadium , copper (to harden), iron , manganese , molybdenum , and other metals. Titanium mill products (sheet, plate, bar, wire, forgings, castings) find application in industrial, aerospace, recreational, and emerging markets. Powdered titanium

4277-514: Is widely used in organic chemistry as a Lewis acid , for example in the Mukaiyama aldol condensation . In the van Arkel–de Boer process , titanium tetraiodide (TiI 4 ) is generated in the production of high purity titanium metal. Titanium(III) and titanium(II) also form stable chlorides. A notable example is titanium(III) chloride (TiCl 3 ), which is used as a catalyst for production of polyolefins (see Ziegler–Natta catalyst ) and

4368-1166: The Bingham Canyon Mine in Utah and the Chuquicamata mine in northern Chile produce molybdenum as a byproduct of copper-mining. About 86% of molybdenum produced is used in metallurgy , with the rest used in chemical applications. The estimated global use is structural steel 35%, stainless steel 25%, chemicals 14%, tool & high-speed steels 9%, cast iron 6%, molybdenum elemental metal 6%, and superalloys 5%. Molybdenum can withstand extreme temperatures without significantly expanding or softening, making it useful in environments of intense heat, including military armor, aircraft parts, electrical contacts, industrial motors, and supports for filaments in light bulbs . Most high-strength steel alloys (for example, 41xx steels ) contain 0.25% to 8% molybdenum. Even in these small portions, more than 43,000 tonnes of molybdenum are used each year in stainless steels , tool steels , cast irons, and high-temperature superalloys . Molybdenum

4459-716: The Defense National Stockpile Center , until the stockpile was dispersed in the 2000s. As of 2021, the four leading producers of titanium sponge were China (52%), Japan (24%), Russia (16%) and Kazakhstan (7%). The Hunter process was the first industrial process to produce pure metallic titanium. It was invented in 1910 by Matthew A. Hunter , a chemist born in New Zealand who worked in the United States. The process involves reducing titanium tetrachloride (TiCl 4 ) with sodium (Na) in

4550-715: The Drakensberg Group of the Great Karoo Basin, South Africa, and the basalts of the Tuli Basin in Botswana and Zimbabwe. Titanium Titanium is a chemical element ; it has symbol Ti and atomic number 22. Found in nature only as an oxide , it can be reduced to produce a lustrous transition metal with a silver color , low density , and high strength, resistant to corrosion in sea water , aqua regia , and chlorine . Titanium

4641-572: The electrochemical principles involved in the recovery of metals from aqueous solutions and fused salt electrolytes", with particular attention paid to titanium. While some metals such as nickel and copper can be refined by electrowinning at room temperature, titanium must be in the molten state and "there is a strong chance of attack of the refractory lining by molten titanium." Zhang et al concluded their Perspective on Thermochemical and Electrochemical Processes for Titanium Metal Production in 2017 that "Even though there are strong interests in

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4732-484: The sol-gel process . Titanium isopropoxide is used in the synthesis of chiral organic compounds via the Sharpless epoxidation . Titanium forms a variety of sulfides, but only TiS 2 has attracted significant interest. It adopts a layered structure and was used as a cathode in the development of lithium batteries . Because Ti(IV) is a "hard cation" , the sulfides of titanium are unstable and tend to hydrolyze to

4823-540: The +3 oxidation state are also numerous. Commonly, titanium adopts an octahedral coordination geometry in its complexes, but tetrahedral TiCl 4 is a notable exception. Because of its high oxidation state, titanium(IV) compounds exhibit a high degree of covalent bonding . The most important oxide is TiO 2 , which exists in three important polymorphs ; anatase, brookite, and rutile. All three are white diamagnetic solids, although mineral samples can appear dark (see rutile ). They adopt polymeric structures in which Ti

4914-464: The ASTM specifications, titanium alloys are also produced to meet aerospace and military specifications (SAE-AMS, MIL-T), ISO standards, and country-specific specifications, as well as proprietary end-user specifications for aerospace, military, medical, and industrial applications. Commercially pure flat product (sheet, plate) can be formed readily, but processing must take into account of the tendency of

5005-459: The Earth's crust with an average of 1.5 parts per million and the 25th most abundant element in the oceans, with an average of 10 parts per billion; it is the 42nd most abundant element in the Universe. The Soviet Luna 24 mission discovered a molybdenum-bearing grain (1 × 0.6 μm) in a pyroxene fragment taken from Mare Crisium on the Moon . The comparative rarity of molybdenum in

5096-478: The Earth's crust is offset by its concentration in a number of water-insoluble ores, often combined with sulfur in the same way as copper, with which it is often found. Though molybdenum is found in such minerals as wulfenite (PbMoO 4 ) and powellite (CaMoO 4 ), the main commercial source is molybdenite (Mo S 2 ). Molybdenum is mined as a principal ore and is also recovered as a byproduct of copper and tungsten mining. The world's production of molybdenum

5187-855: The Zambezi valley. The Batoka Formation is found in Botswana , Zambia , Zimbabwe , in the Mid-Zambezi, Mana Pools and Cabora Bassa Basins. Lavas of the Batoka Formation have been dated at 180 to 179 Ma. The Batoka Formation is the uppermost formation in the Upper Karoo Group of the Karoo Supergroup , lying above the Forest Sandstone Formation . The Batoka Formation has been correlated to

5278-471: The alloys on a large scale were hampered with inconsistent results, a tendency toward brittleness, and recrystallization. In 1906, William D. Coolidge filed a patent for rendering molybdenum ductile , leading to applications as a heating element for high-temperature furnaces and as a support for tungsten-filament light bulbs; oxide formation and degradation require that molybdenum be physically sealed or held in an inert gas. In 1913, Frank E. Elmore developed

5369-484: The butyrate and perfluorobutyrate dimers, Mo 2 (O 2 CR) 4 and Rh 2 (O 2 CR) 4 , have been reported. The oxidation state 0 and lower are possible with carbon monoxide as ligand, such as in molybdenum hexacarbonyl , Mo(CO) 6 . Molybdenite —the principal ore from which molybdenum is now extracted—was previously known as molybdena. Molybdena was confused with and often utilized as though it were graphite . Like graphite, molybdenite can be used to blacken

5460-471: The creation of potentially effective, selective, and stable titanium-based drugs. Titanium was discovered in 1791 by the clergyman and geologist William Gregor as an inclusion of a mineral in Cornwall , Great Britain. Gregor recognized the presence of a new element in ilmenite when he found black sand by a stream and noticed the sand was attracted by a magnet . Analyzing the sand, he determined

5551-524: The early 1950s, titanium came into use extensively in military aviation, particularly in high-performance jets, starting with aircraft such as the F-100 Super Sabre and Lockheed A-12 and SR-71 . Throughout the Cold War period, titanium was considered a strategic material by the U.S. government, and a large stockpile of titanium sponge (a porous form of the pure metal) was maintained by

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5642-558: The industry for finding a better method to produce Ti metal, and a large number of new concepts and improvements have been investigated at the laboratory or even at pilot plant scales, there is no new process to date that can replace the Kroll process commercially." The Hydrogen assisted magnesiothermic reduction (HAMR) process uses titanium dihydride . All welding of titanium must be done in an inert atmosphere of argon or helium to shield it from contamination with atmospheric gases (oxygen, nitrogen, and hydrogen). Contamination causes

5733-522: The laboratory until 1932 when William Justin Kroll produced it by reducing titanium tetrachloride (TiCl 4 ) with calcium . Eight years later he refined this process with magnesium and with sodium in what became known as the Kroll process. Although research continues to seek cheaper and more efficient routes, such as the FFC Cambridge process , the Kroll process is still predominantly used for commercial production. Titanium of very high purity

5824-585: The liver and kidneys and lower in the vertebrae. Molybdenum is also present within human tooth enamel and may help prevent its decay. Acute toxicity has not been seen in humans, and the toxicity depends strongly on the chemical state. Studies on rats show a median lethal dose (LD 50 ) as low as 180 mg/kg for some Mo compounds. Although human toxicity data is unavailable, animal studies have shown that chronic ingestion of more than 10 mg/day of molybdenum can cause diarrhea, growth retardation, infertility , low birth weight, and gout ; it can also affect

5915-588: The lowest coefficients of thermal expansion among commercially used metals. Molybdenum is a transition metal with an electronegativity of 2.16 on the Pauling scale. It does not visibly react with oxygen or water at room temperature, but is attacked by halogens and hydrogen peroxide. Weak oxidation of molybdenum starts at 300 °C (572 °F); bulk oxidation occurs at temperatures above 600 °C, resulting in molybdenum trioxide . Like many heavier transition metals, molybdenum shows little inclination to form

6006-415: The lungs, kidneys, and liver. Sodium tungstate is a competitive inhibitor of molybdenum. Dietary tungsten reduces the concentration of molybdenum in tissues. Low soil concentration of molybdenum in a geographical band from northern China to Iran results in a general dietary molybdenum deficiency and is associated with increased rates of esophageal cancer . Compared to the United States, which has

6097-431: The material can gall unless sharp tools and proper cooling methods are used. Like steel structures, those made from titanium have a fatigue limit that guarantees longevity in some applications. The metal is a dimorphic allotrope of a hexagonal close packed α form that changes into a body-centered cubic (lattice) β form at 882 °C (1,620 °F). The specific heat of the α form increases dramatically as it

6188-503: The metal to springback . This is especially true of certain high-strength alloys. Exposure to the oxygen in air at the elevated temperatures used in forging results in formation of a brittle oxygen-rich metallic surface layer called " alpha case " that worsens the fatigue properties, so it must be removed by milling, etching, or electrochemical treatment. The working of titanium is very complicated, and may include Friction welding , cryo-forging , and Vacuum arc remelting . Titanium

6279-453: The mineral in which it resided, and from which it might be isolated. Peter Jacob Hjelm successfully isolated molybdenum using carbon and linseed oil in 1781. For the next century, molybdenum had no industrial use. It was relatively scarce, the pure metal was difficult to extract, and the necessary techniques of metallurgy were immature. Early molybdenum steel alloys showed great promise of increased hardness, but efforts to manufacture

6370-403: The most abundant (73.8%). As a metal , titanium is recognized for its high strength-to-weight ratio . It is a strong metal with low density that is quite ductile (especially in an oxygen -free environment), lustrous, and metallic-white in color . Due to its relatively high melting point (1,668 °C or 3,034 °F) it has sometimes been described as a refractory metal , but this

6461-507: The most abundant (73.8% natural abundance ). At least 21 radioisotopes have been characterized, the most stable of which are Ti with a half-life of 63 years; Ti, 184.8 minutes; Ti, 5.76 minutes; and Ti, 1.7 minutes. All other radioactive isotopes have half-lives less than 33 seconds, with the majority less than half a second. The isotopes of titanium range in atomic weight from 39.002  Da ( Ti) to 63.999 Da ( Ti). The primary decay mode for isotopes lighter than Ti

6552-560: The most common bacterial catalysts for breaking the chemical bond in atmospheric molecular nitrogen in the process of biological nitrogen fixation . At least 50 molybdenum enzymes are now known in bacteria, plants, and animals, although only bacterial and cyanobacterial enzymes are involved in nitrogen fixation. Most nitrogenases contain an iron–molybdenum cofactor FeMoco , which is believed to contain either Mo(III) or Mo(IV). By contrast Mo(VI) and Mo(IV) are complexed with molybdopterin in all other molybdenum-bearing enzymes. Molybdenum

6643-530: The oxide with release of hydrogen sulfide . Titanium nitride (TiN) is a refractory solid exhibiting extreme hardness, thermal/electrical conductivity, and a high melting point. TiN has a hardness equivalent to sapphire and carborundum (9.0 on the Mohs scale ), and is often used to coat cutting tools, such as drill bits . It is also used as a gold-colored decorative finish and as a barrier layer in semiconductor fabrication . Titanium carbide (TiC), which

6734-414: The pervasiveness of the chromium(III) compounds. The highest oxidation state is seen in molybdenum(VI) oxide (MoO 3 ), whereas the normal sulfur compound is molybdenum disulfide MoS 2 . From the perspective of commerce, the most important compounds are molybdenum disulfide ( MoS 2 ) and molybdenum trioxide ( MoO 3 ). The black disulfide is the main mineral. It is roasted in air to give

6825-475: The presence of chlorine . In this process, the chlorine gas is passed over a red-hot mixture of rutile or ilmenite in the presence of carbon. After extensive purification by fractional distillation , the TiCl 4 is reduced with 800 °C (1,470 °F) molten magnesium in an argon atmosphere. The van Arkel–de Boer process was the first semi-industrial process for pure Titanium. It involves thermal decomposition of titanium tetraiodide . Titanium powder

6916-505: The presence of titanium dioxide impurities. A variety of reduced oxides ( suboxides ) of titanium are known, mainly reduced stoichiometries of titanium dioxide obtained by atmospheric plasma spraying . Ti 3 O 5 , described as a Ti(IV)-Ti(III) species, is a purple semiconductor produced by reduction of TiO 2 with hydrogen at high temperatures, and is used industrially when surfaces need to be vapor-coated with titanium dioxide: it evaporates as pure TiO, whereas TiO 2 evaporates as

7007-440: The presence of two metal oxides: iron oxide (explaining the attraction to the magnet) and 45.25% of a white metallic oxide he could not identify. Realizing that the unidentified oxide contained a metal that did not match any known element, in 1791 Gregor reported his findings in both German and French science journals: Crell's Annalen and Observations et Mémoires sur la Physique . He named this oxide manaccanite . Around

7098-403: The rest of Asia (mostly Armenia, Russia, Iran and Mongolia) produce the remainder. In molybdenite processing, the ore is first roasted in air at a temperature of 700 °C (1,292 °F). The process gives gaseous sulfur dioxide and the molybdenum(VI) oxide : The resulting oxide is then usually extracted with aqueous ammonia to give ammonium molybdate: Copper, an impurity in molybdenite,

7189-760: The same time, Franz-Joseph Müller von Reichenstein produced a similar substance, but could not identify it. The oxide was independently rediscovered in 1795 by Prussian chemist Martin Heinrich Klaproth in rutile from Boinik (the German name of Bajmócska), a village in Hungary (now Bojničky in Slovakia). Klaproth found that it contained a new element and named it for the Titans of Greek mythology . After hearing about Gregor's earlier discovery, he obtained

7280-409: The strength of pure Mo, and is more ductile and more weldable, yet in tests it resisted corrosion of a standard eutectic salt ( FLiBe ) and salt vapors used in molten salt reactors for 1100 hours with so little corrosion that it was difficult to measure. Due to its excellent mechanical properties under high temperature and high pressure, TZM alloys are extensively applied in the military industry. It

7371-517: The success of platinum-based chemotherapy, titanium(IV) complexes were among the first non-platinum compounds to be tested for cancer treatment. The advantage of titanium compounds lies in their high efficacy and low toxicity in vivo . In biological environments, hydrolysis leads to the safe and inert titanium dioxide. Despite these advantages the first candidate compounds failed clinical trials due to insufficient efficacy to toxicity ratios and formulation complications. Further development resulted in

7462-420: The super-heavy howitzer Big Bertha , because traditional steel melts at the temperatures produced by the propellant of the one ton shell. After the war, demand plummeted until metallurgical advances allowed extensive development of peacetime applications. In World War II , molybdenum again saw strategic importance as a substitute for tungsten in steel alloys. Molybdenum is the 54th most abundant element in

7553-453: The surface. Molybdenum is also used to enhance the corrosion resistance of ferritic (for example grade 444) and martensitic (for example 1.4122 and 1.4418) stainless steels. Because of its lower density and more stable price, molybdenum is sometimes used in place of tungsten. An example is the 'M' series of high-speed steels such as M2, M4 and M42 as substitution for the 'T' steel series, which contain tungsten. Molybdenum can also be used as

7644-528: The top and base of each flow. The basalt mineralogy consists of mainly of plagioclase , augite , magnetite , some ilmenite and volcanic glass . In the Hwange area, vesicles consist mostly of quartz , chalcedony or calcite , though zeolites , such as stilbite , mesolite and laumontite , are dominant towards Victoria Falls and in the lower Deka valley, and are common in north-eastern Botswana. The basalt lavas are related to carbonatite intrusions in

7735-678: The trioxide: The trioxide, which is volatile at high temperatures, is the precursor to virtually all other Mo compounds as well as alloys. Molybdenum has several oxidation states , the most stable being +4 and +6 (bolded in the table at left). Molybdenum(VI) oxide is soluble in strong alkaline water, forming molybdates (MoO 4 ). Molybdates are weaker oxidants than chromates . They tend to form structurally complex oxyanions by condensation at lower pH values, such as [Mo 7 O 24 ] and [Mo 8 O 26 ] . Polymolybdates can incorporate other ions, forming polyoxometalates . The dark-blue phosphorus -containing heteropolymolybdate P[Mo 12 O 40 ]

7826-485: The world production of the element (about 80%) is used in steel alloys, including high-strength alloys and superalloys . Most molybdenum compounds have low solubility in water. Heating molybdenum-bearing minerals under oxygen and water affords molybdate ion MoO 4 , which forms quite soluble salts. Industrially, molybdenum compounds (about 14% of world production of the element) are used as pigments and catalysts . Molybdenum-bearing enzymes are by far

7917-588: Was 250,000 tonnes in 2011, the largest producers being China (94,000 t), the United States (64,000 t), Chile (38,000 t), Peru (18,000 t) and Mexico (12,000 t). The total reserves are estimated at 10 million tonnes, and are mostly concentrated in China (4.3 Mt), the US (2.7 Mt) and Chile (1.2 Mt). By continent, 93% of world molybdenum production is about evenly shared between North America, South America (mainly in Chile), and China. Europe and

8008-517: Was discovered (in the sense of differentiating it as a new entity from the mineral salts of other metals) in 1778 by Carl Wilhelm Scheele . The metal was first isolated in 1781 by Peter Jacob Hjelm . Molybdenum does not occur naturally as a free metal on Earth; in its minerals, it is found only in oxidized states . The free element, a silvery metal with a grey cast, has the sixth-highest melting point of any element. It readily forms hard, stable carbides in alloys , and for this reason most of

8099-415: Was discovered in Cornwall , Great Britain , by William Gregor in 1791 and was named by Martin Heinrich Klaproth after the Titans of Greek mythology . The element occurs within a number of minerals , principally rutile and ilmenite , which are widely distributed in the Earth's crust and lithosphere ; it is found in almost all living things, as well as bodies of water, rocks, and soils. The metal

8190-482: Was made in small quantities when Anton Eduard van Arkel and Jan Hendrik de Boer discovered the iodide process in 1925, by reacting with iodine and decomposing the formed vapors over a hot filament to pure metal. In the 1950s and 1960s, the Soviet Union pioneered the use of titanium in military and submarine applications ( Alfa class and Mike class ) as part of programs related to the Cold War. Starting in

8281-482: Was never employed widely and was later lost. In the West in 1754, Bengt Andersson Qvist examined a sample of molybdenite and determined that it did not contain lead and thus was not galena. By 1778 Swedish chemist Carl Wilhelm Scheele stated firmly that molybdena was (indeed) neither galena nor graphite. Instead, Scheele correctly proposed that molybdena was an ore of a distinct new element, named molybdenum for

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