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Lutetium is a chemical element with the symbol Lu and atomic number 71. It is a silvery white metal, which resists corrosion in dry air, but not in moist air. Lutetium is the last element in the lanthanide series, and it is traditionally counted among the rare earth elements; it can also be classified as the first element of the 6th-period transition metals.
Thorium is a weakly radioactive metallic chemical element with the symbol Th and atomic number 90. Thorium is light silver and tarnishes olive gray when it is exposed to air, forming thorium dioxide; it is moderately soft and malleable and has a high melting point. Thorium is an electropositive actinide whose chemistry is dominated by the +4 oxidation state; it is quite reactive and can ignite in air when finely divided.
Zircon is a mineral belonging to the group of nesosilicates and is a source of the metal zirconium. Its chemical name is zirconium(IV) silicate, and its corresponding chemical formula is ZrSiO4. An empirical formula showing some of the range of substitution in zircon is (Zr1–y, REEy)(SiO4)1–x(OH)4x–y. Zircon precipitates from silicate melts and has relatively high concentrations of high field strength incompatible elements. For example, hafnium is almost always present in quantities ranging from 1 to 4%. The crystal structure of zircon is tetragonal crystal system. The natural color of zircon varies between colorless, yellow-golden, red, brown, blue, and green.
Baddeleyite is a rare zirconium oxide mineral (ZrO2 or zirconia), occurring in a variety of monoclinic prismatic crystal forms. It is transparent to translucent, has high indices of refraction, and ranges from colorless to yellow, green, and dark brown. See etymology below.
Zirconium dioxide is a white crystalline oxide of zirconium. Its most naturally occurring form, with a monoclinic crystalline structure, is the mineral baddeleyite. A dopant stabilized cubic structured zirconia, cubic zirconia, is synthesized in various colours for use as a gemstone and a diamond simulant.
Mischmetal (from German: Mischmetall – "mixed metal") is an alloy of rare-earth elements. It is also called cerium mischmetal, or rare-earth mischmetal. A typical composition includes approximately 55% cerium, 25% lanthanum, and 15~18% neodymium, with traces of other rare earth metals; it contains 95% lanthanides and 5% iron. Its most common use is in the pyrophoric ferrocerium "flint" ignition device of many lighters and torches, although an alloy of only rare-earth elements would be too soft to give good sparks. For this purpose, it is blended with iron oxide and magnesium oxide to form a harder material known as ferrocerium. In chemical formulae it is commonly abbreviated as Mm, e.g. MmNi5.
Carl Auer von Welsbach, who received the Austrian noble title of Freiherr Auer von Welsbach in 1901, was an Austrian scientist and inventor, who separated didymium into the elements neodymium and praseodymium in 1885. He was also one of three scientists to independently discover the element lutetium, separating it from ytterbium in 1907, setting off the longest priority dispute in the history of chemistry.
Monazite is a primarily reddish-brown phosphate mineral that contains rare-earth elements. Due to variability in composition, monazite is considered a group of minerals. The most common species of the group is monazite-(Ce), that is, the cerium-dominant member of the group. It occurs usually in small isolated crystals. It has a hardness of 5.0 to 5.5 on the Mohs scale of mineral hardness and is relatively dense, about 4.6 to 5.7 g/cm3. There are five different most common species of monazite, depending on the relative amounts of the rare earth elements in the mineral:
Praseodymium is a chemical element with the symbol Pr and the atomic number 59. It is the third member of the lanthanide series and is considered one of the rare-earth metals. It is a soft, silvery, malleable and ductile metal, valued for its magnetic, electrical, chemical, and optical properties. It is too reactive to be found in native form, and pure praseodymium metal slowly develops a green oxide coating when exposed to air.
An incandescent gas mantle, gas mantle or Welsbach mantle is a device for generating incandescent bright white light when heated by a flame. The name refers to its original heat source in gas lights which illuminated the streets of Europe and North America in the late 19th century. Mantle refers to the way it hangs like a cloak above the flame. Gas mantles were also used in portable camping lanterns, pressure lanterns and some oil lamps.
Metamictisation is a natural process resulting in the gradual and ultimately complete destruction of a mineral's crystal structure, leaving the mineral amorphous. The affected material is therefore described as metamict.
Thorium dioxide (ThO2), also called thorium(IV) oxide, is a crystalline solid, often white or yellow in colour. Also known as thoria, it is produced mainly as a by-product of lanthanide and uranium production. Thorianite is the name of the mineralogical form of thorium dioxide. It is moderately rare and crystallizes in an isometric system. The melting point of thorium oxide is 3300 °C – the highest of all known oxides. Only a few elements (including tungsten and carbon) and a few compounds (including tantalum carbide) have higher melting points. All thorium compounds, including the dioxide, are radioactive because there are no stable isotopes of thorium.
Thorite, (Th,U)SiO4, is a rare nesosilicate of thorium that crystallizes in the tetragonal system and is isomorphous with zircon and hafnon. It is the most common mineral of thorium and is nearly always strongly radioactive. It was named in 1829 to reflect its thorium content. Thorite was discovered in 1828 on the island of Løvøya, Norway, by the vicar and mineralogist, Hans Morten Thrane Esmark, who sent the first specimens of this black mineral to his father, Jens Esmark, who was a professor of mineralogy and geology.
Xenotime is a rare-earth phosphate mineral, the major component of which is yttrium orthophosphate (YPO4). It forms a solid solution series with chernovite-(Y) (YAsO4) and therefore may contain trace impurities of arsenic, as well as silicon dioxide and calcium. The rare-earth elements dysprosium, erbium, terbium and ytterbium, as well as metal elements such as thorium and uranium (all replacing yttrium) are the expressive secondary components of xenotime. Due to uranium and thorium impurities, some xenotime specimens may be weakly to strongly radioactive. Lithiophyllite, monazite and purpurite are sometimes grouped with xenotime in the informal "anhydrous phosphates" group. Xenotime is used chiefly as a source of yttrium and heavy lanthanide metals (dysprosium, ytterbium, erbium and gadolinium). Occasionally, gemstones are also cut from the finest xenotime crystals.
Ferrocerium is a synthetic pyrophoric alloy of mischmetal hardened by blending in oxides of iron and/or magnesium. When struck with a harder material, the mixture produces hot sparks that can reach temperatures of 3,315 °C (6,000 °F) when rapidly oxidized by the process of striking the rod. Striking both scrapes fragments off, exposing them to the oxygen in the air, and easily ignites them by friction heat due to cerium's remarkably low ignition temperature of between 150 and 180 °C.
Thorianite is a rare thorium oxide mineral, ThO2. It was originally described by Ananda Coomaraswamy in 1904 as uraninite, but recognized as a new species by Wyndham R. Dunstan. It was so named by Dunstan on account of its high percentage of thorium; it also contains the oxides of uranium, lanthanum, cerium, praseodymium and neodymium. Helium is present, and the mineral is slightly less radioactive than pitchblende, but is harder to shield due to its high energy gamma rays. It is common in the alluvial gem-gravels of Sri Lanka, where it occurs mostly as water worn, small, heavy, black, cubic crystals. The largest crystals are usually near 1.5 cm. Larger crystals, up to 6 cm (2.4 in), have been reported from Madagascar.
Uranium–lead dating, abbreviated U–Pb dating, is one of the oldest and most refined of the radiometric dating schemes. It can be used to date rocks that formed and crystallised from about 1 million years to over 4.5 billion years ago with routine precisions in the 0.1–1 percent range.
Lutetium(III) oxide, a white solid, is a cubic compound of lutetium sometimes used in the preparation of specialty glasses. It is also called lutecia. It is a lanthanide oxide, also known as a rare earth.
Cerium is a chemical element with the symbol Ce and atomic number 58. Cerium is a soft, ductile, and silvery-white metal that tarnishes when exposed to air. Cerium is the second element in the lanthanide series, and while it often shows the oxidation state of +3 characteristic of the series, it also has a stable +4 state that does not oxidize water. It is also considered one of the rare-earth elements. Cerium has no known biological role in humans but is not particularly toxic, except with intense or continued exposure.
Treibacher Industrie AG is a chemical and metallurgical company based in Treibach in Carinthia, Austria. It was founded in 1898 by Dr. Carl Auer von Welsbach, the inventor of the incandescent mantle and the lighter "flint" (ferrocerium) as Treibacher Chemische Werke. The company emploey approximately 900 people worldwide and generated sales of 498 million euros in 2020.
References
- Rines, George Edwin, ed. (1920). . Encyclopedia Americana .
- B. H. Brough, abstractor (1889). "Auerlite, a new Thorium Mineral". Journal of the Chemical Society. Royal Society of Chemistry. 56, Part 1: 221–2. This work in turn cites:
- W. E. Hidden and J. B. Mackintosh (1888). "Auerlite, a new Thorium Mineral". American Journal of Science. 36 (216): 461–463. doi: 10.2475/ajs.s3-36.216.461 . S2CID 130031763.