Medal Georges Urbain Rare Earth Metals Celtium Scandium, 1938

Description: 166-tir36Bronze medal, France. Struck in 1938, beautiful patina, some minor flaws, some traces of oxidation.Engraver / Artist : N. Aronson.Dimension : 60 mm by 80 mm.Weight : 206 g.Metal : Bronze .Mark on the edge : triangle + bronze.Fast and careful shipping.The support is not for sale.The stand is not for sale. Rare earths are a group of metals with similar properties including scandium 21Sc, yttrium 39Y and the fifteen lanthanides.These metals are, contrary to what their name suggests, quite widespread in the earth's crust, like certain common metals. The abundance of cerium is thus approximately 48 ppm1, while that of thulium and lutetium is only 0.5 ppm. In elemental form, rare earths have a metallic appearance and are quite soft, malleable and ductile. These elements are chemically quite reactive, especially at high temperatures or when finely divided.Their electromagnetic properties come from their electronic configuration with progressive filling of the 4f subshell, at the origin of the phenomenon called lanthanide contraction.It was not until the Manhattan Project in the 1940s that rare earths were purified on an industrial level, and until the 1970s that one of them, yttrium, found mass application in the manufacture of phosphors for cathode ray tubes used in color television. From the perspective of the global economy, rare earths are now among the strategic raw materials. The following table gives the atomic number, symbol, name, etymology and uses of the 17 rare earths.The name of a rare earth derives depending on the case: from the place name of the discovery (Ytterby, Scandinavia); named after a discoverer (Gadolin, Samarski); from mythology (Ceres, Prometheus, Thule); circumstances of the discovery (see La, Pr, Nd, Dy).Z Symbol Name Etymology Uses2,3,4,521 Sc Scandium from Latin Scandia (Scandinavia). Light aluminum-scandium alloys: military aeronautics; additive (ScI2) in metal halide lamps; 46Sc: radioactive tracer in refineries.39 Y Yttrium from the village of Ytterby, Sweden, where the first rare earth mineral was discovered. Lasers: Lanthanide6 (Nd, Ho, Er, Tm, Yb)-doped yttrium aluminum garnet (YAG); Eu-doped YVO4 vanadate: red phosphors (TV), Nd-doped: lasers, Ce3+-doped: GaN LEDs; compact fluorescent bulbs; yttrium barium copper mixed oxide (YBCO): high-temperature superconductors; yttrium-stabilized cubic zirconia (YSZ): refractory conductive ceramics; yttrium iron garnet (YIG): microwave filters; spark plugs; 90Y: cancer treatment.57 Lanthanum from the Greek λανθάνειν, “hidden”. Nickel-metal hydride batteries; high refractive index and low dispersion glasses; laser (YLaF); fluoride glasses; hydrogen storage.58 This Cerium from the dwarf planet Ceres, named after the Roman goddess of agriculture. Oxidizing chemical agent; glass polishing powder (CeO2); yellow colorant in glasses and ceramics; glass discoloration; catalysts: self-cleaning furnace coatings, hydrocarbon cracking, exhaust pipes; Ce-doped YAG: yellow-green phosphor for light-emitting diodes; Incandescent mantles.59 Pr Praseodymium from the Greek πράσινος, “pale green”, and δίδυμος, “twin”. Permanent magnets (Nd alloyed); Fiber amplifiers; Glass (green) and ceramic (yellow) dyes; Welding goggles (Nd alloyed).60 Nd Neodymium from the Greek νεο-, “new” and δίδυμος, “twin”. Permanent magnets (wind turbines; small hydroelectric power plants; hybrid cars); YAG lasers; violet dye in glasses and ceramics; ceramic capacitors; welding goggles (Pr alloyed).61 Pm Promethium of the Titan Prometheus, who brought fire to mortals. Potential applications of 147Pm: luminous paints, nuclear batteries, energy source for space probes.62 Sm Samarium of Russian mining engineer Vasily Samarsky-Bykhovets. Permanent magnets (SmCo5); X-ray lasers7; catalysts; neutron capture; masers; 153Sm: radiotherapy.63 Eu Europium of the continent Europe. Red (Eu3+) and blue (Eu2+) phosphors: compact fluorescent lamps, X-ray intensifying screens, TV; lasers; crypts: biological probes by energy transfer between fluorescent molecules; control rods (nuclear reactors).64 Gd Gadolinium by Johan Gadolin, discoverer of yttrium in 1794. Lasers; neutron capture: nuclear reactors; contrast agent in MRI8; green phosphors; X-ray intensifying screens; steel additive.65 Tb Terbium from the village of Ytterby, Sweden. Green phosphors: compact fluorescent lamps, X-ray intensifying screens, TV; lasers; cryptates (see Eu); Terfenol-D (Tb0.3Dy0.7Fe1.9): magnetostriction, transducers.66 Dy Dysprosium from Greek δυσπρόσιτος, “difficult to obtain”. Permanent magnets; metal halide lamps; hard disks; lasers; Terfenol-D (see Tb).67 Ho Holmium from Latin Holmia (latinized form63 Eu Europium of the continent Europe. Red (Eu3+) and blue (Eu2+) phosphors: compact fluorescent lamps, X-ray intensifying screens, TV; lasers; crypts: biological probes by energy transfer between fluorescent molecules; control rods (nuclear reactors).64 Gd Gadolinium by Johan Gadolin, discoverer of yttrium in 1794. Lasers; neutron capture: nuclear reactors; contrast agent in MRI8; green phosphors; X-ray intensifying screens; steel additive.65 Tb Terbium from the village of Ytterby, Sweden. Green phosphors: compact fluorescent lamps, X-ray intensifying screens, TV; lasers; cryptates (see Eu); Terfenol-D (Tb0.3Dy0.7Fe1.9): magnetostriction, transducers.66 Dy Dysprosium from Greek δυσπρόσιτος, “difficult to obtain”. Permanent magnets; metal halide lamps; hard disks; lasers; Terfenol-D (see Tb).67 Ho Holmium from Latin Holmia (latinized form of Stockholm). Infrared surgical lasers; pink glass dye; spectrophotometry calibration standard; permanent magnets.68 Er Erbium from the village of Ytterby (Sweden). Infrared lasers (dentistry); Fiber amplifiers; pink coloring of glasses and ceramics.69 Tm Thulium from the mythological northern land, Thule. Blue phosphors for X-ray intensifying screens; high temperature superconductors; infrared YAG lasers; 170Tm: brachytherapy, portable radiography.70 Yb Ytterbium from the village of Ytterby (Sweden). Near infrared lasers; atomic clock; stainless steel; 169Yb: portable radiography.71 Lu Lutecium of Lutetia (old name of Paris). Detectors in positron emission tomography; tantalate LuTaO4 host of phosphors for electrons and X-rays.Unseparated rare earth metals, or mischmetal, have additional uses: Ferrocerium from lighter flints steel additives (deoxidation, desulfurization) hydrocarbon cracking catalysts.First discoveries and namingDiscoveries of rare earths.Yttrium (1794) Yttrium Terbium (1843) Erbium (1843) Erbium Erbium Thulium (1879) Holmium (1879) Holmium Dysprosium (1886) Ytterbium (1878) Ytterbium Ytterbium Lutetium (1907) Scandium (1879)Cerium (1803) CeriumLanthanum (1839) LanthanumDidymus (1839) Didyma Neodymium (1885) Praseodymium (1885)Samarium (1879) Samarium Samarium Europium (1901) Gadolinium (1880) &nThese metals are, contrary to what their name suggests, quite widespread in the earth's crust, like certain common metals. The abundance of cerium is thus approximately 48 ppm1, while that of thulium and lutetium is only 0.5 ppm. In elemental form, rare earths have a metallic appearance and are quite soft, malleable and ductile. These elements are chemically quite reactive, especially at high temperatures or when finely divided. 39 Y Yttrium from the village of Ytterby, Sweden, where the first rare earth mineral was discovered. Lasers: Lanthanide6 (Nd, Ho, Er, Tm, Yb)-doped yttrium aluminum garnet (YAG); Eu-doped YVO4 vanadate: red phosphors (TV), Nd-doped: lasers, Ce3+-doped: GaN LEDs; compact fluorescent bulbs; yttrium barium copper mixed oxide (YBCO): high-temperature superconductors; y

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