Dysprosium earths

Some nut trees accumulate mineral elements. Hickory nut is notable as an accumulator of aluminum compounds (30) the ash of its leaves contains up to 37.5% of AI2O2, compared with only 0.032% of aluminum oxide in the ash of the Fnglish walnut s autumn leaves. As an accumulator of rare-earth elements, hickory greatly exceeds all other plants their leaves show up to 2296 ppm of rare earths (scandium, yttrium, lanthanum, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium). The amounts of rare-earth elements found in parts of the hickory nut are kernels, at 5 ppm shells, at 7 ppm and shucks, at 17 ppm. The kernel of the Bra2d nut contains large amounts of barium in an insoluble form when the nut is eaten, barium dissolves in the hydrochloric acid of the stomach. 

Rare earth elements, with relatively high thermal neutron activation cross-sections, have been tested or considered as tagging species for this purpose. At GA (Ref 8), preliminary expts were conducted with 0.38 cal ammo using dysprosium (Dy) and europium (Eu) deposited on the wall of the cartridge case and in the gunpowder, and Dy, hoKnium (Ho) and indium (In) in the primer. 

The compounds of the rare earth elements are usually highly colored. Neodymium s compounds are mainly lavender and violet, samarium s yellow and brown, holmium s yellow and orange, and erbium s rose-pink. Europium makes pink salts which evaporate easily. Dysprosium makes greenish yellow compounds, and ytterbium, yellow-gold. Compounds of lutetium are colorless, and compounds of terbium are colorless, dark brown, or black. 

A further strategy to achieve white emission uses rare-earth complexes. For example, a dysprosium complex (245) emits two band emissions a yellow band (580 nm) corresponding to the 4F9/2 —> 6Hi3/2 transition and a blue band (480 nm) corresponding to 4F9/2 — 6H15/2 transition of Dy3+ ion in the complex. Li et al. reported Dy-complex white emission OLEDs of a structure of ITO/PVK Dy complex/Mg Ag device [276], Figure 3.13 shows the PL and EL emission spectra of such a complex and its device, respectively. 

Rare earth. One of a group of 15 chemically related elements lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. 

Dysprosium - the atomic number is 66 and the chemical symbol is Dy. The name derives from the Greek dysprositos for hard to get at , due to the difficulty in separating this rare earth element from a holmium mineral in which it was found. Discovery was first claimed by the Swiss chemist Marc Delafontaine in the mineral samarskite in 1878 and he called it philippia. Philippia was subsequently found to be a mixture of terbium and erbium. Dysprosium was later discovered in a holmium sample by the French chemist Paul-Emile Lecoq de Boisbaudron in 1886, who was then credited with the discovery. It was first isolated by the French chemist George Urbain in 1906. 

Gadolinium is silvery-white, soft, malleable, and ductile with a metallic luster. It is the second of what is referred to as the dysprosium, subgroup in the middle of the lanthanide series of rare-earths. It tarnishes in air, forming the oxide (Gd O ) on the surface, which flakes off the surface, exposing a fresh metal that in turn oxidi2es. 

Dysprosium, with characteristics similar to most of the other rare-earths, was difficult to discover. Although dysprosium does not react rapidly with moist air at low temperatures, it... 

Dysprosium is the 43rd most abundant element on Earth and ranks ninth in abundance of the rare-earths found in the Earth s crust. It is a metallic element that is usually found as an oxide (disprosia). Like most rare-earths, it is found in the minerals monazite and allanite, which are extracted from river sands of India, Africa, South America, and Australia and the beaches of Florida. It is also found in the mineral bastnasite in California. 

Californium is a transuranic element of the actinide series that is homologous with dysprosium (gjDy), just above it in the rare-earth lanthanide series. Cf-245 was the first isotope of californium that was artificially produced. It has a half-life of just 44 minutes. Isotopes of californium are made by subjecting berkelium to high-energy neutrons within nuclear reactors, as follows + (neutrons and A, gamma rays) — °Bk — °Cf + (3- (beta particle... 

Dysprosium was discovered in 1866 by Boisbaudran. It occurs in the earth s crust associated with other rare earth metals. It is found in the minerals, xenotime YPO4, gadolinite, euxemite and monazite (Ce, La, Th)P04. The concentration of dysprosium in seawater is 0.9 ng/L and in the earth s crust 5.2 mg/kg. 

Erbium metal is produced from rare-earth minerals. Methods of preparation are similar to dysprosium, involving sulfuric acid treatment, ion exchange separation from other lanthanides, roasting, conversion to hahde, and finally high temperature reduction with calcium or sodium, (see Dysprosium). 

Holmium is obtained from monazite, bastnasite and other rare-earth minerals as a by-product during recovery of dysprosium, thulium and other rare-earth metals. The recovery steps in production of all lanthanide elements are very similar. These involve breaking up ores by treatment with hot concentrated sulfuric acid or by caustic fusion separation of rare-earths by ion-exchange processes conversion to halide salts and reduction of the hahde(s) to metal (See Dysprosium, Gadolinium and Erbium). 

In the 1990s a breakthrough was achieved in the development of long-lived afterglow phosphors. It was discovered that by co-doping rare earth aluminates, especially strontium, with europium and dysprosium gave phosphors with around ten times the afterglow of copper activated zinc sulfide and also with ten times the... 

Of all the properties of the rare earths that contribute to their many and varied applications one that ranks of special interest is the extremely high thermal neutron capture cross-section associated with the elements gadolinium, samarium, europium and dysprosium, see Table IV. 

French chemist who discovered gallium, samarium, and dysprosium, and perfected methods of separating the rare earths He ranks with Bunsen, Kirch-hofiF, and Crookes as one of the founders of the science of spectroscopy. 

Boisbaudran s researches on the rare earths also yielded a rich harvest of results, for he discovered samarium and dysprosium (2). His investigations in the field of spectroscopy were also of high merit... 

In the year 1886 Lecoq de Boisbaudran separated pure holmia into two earths, which he called holmia and dysprosta. He accomplished this by fractional precipitation, first with ammonium hydroxide and then with a saturated solution of potassium sulfate, and found that the constituents of impure holmium solutions precipitate in the following order terbium, dysprosium, holmium, and erbium (3, 37, 48). Lecoq de Boisbaudran never had an abundant supply of raw materials for his remarkable researches on the rare earths, and he once confided to Professor Urbain that most of his fractionations had been carried out on the marble slab of his fireplace (56). 

The cathodoluminescence of thin films containing rare-earth oxides was studied by Hansen and Myers (140). Films of yttrium oxide doped with rare earths were prepared in vacuum by electron-bombardment evaporation of the oxide powder mixtures. Luminescent rise and decay curves were obtained for activation with europium, gadolinium, terbium, and dysprosium. 

Even more striking in the old tooth is the abundance of rare earths (dysprosium, holmium, erbium, thulium, ytterbium, and lutetium) and the elements tantalum, tungsten, gold, thorium, and uranium. Rare earth minerals are found in Scandinavia (in fact, many rare earth elements were discovered there), but what were they used for Did people prepare food with them Did they somehow get into the food chain ... 

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