Erbium, abundance

Yttrium (j Y) is often confused with another element of the lanthanide series of rare Earths— Ytterbium ( Yb). Also confusing is the fact that the rare-earth elements terbium and erbium were found in the same minerals in the same quarry in Sweden. Yttrium ranks second in abundance of all 16 rare-earth, and Ytterbium ranks 10th. Yttrium is a dark silvery-gray hghtweight metal that, in the form of powder or shavings, will ignite spontaneously. Therefore, it is considered a moderately active rare-earth metal. 

Erbium ranks 17th in abundance among the rare-earths, and it is the 46th most abundant element found in the Earth s crust. It exists in only 2.5 ppm, meaning that about 2.5 pounds of erbium could be extracted from one million pounds of dirt in the Earth s crust. Higher concentrations are found in some areas, but in general, the oxides of erbium are rarher scarce. 

Of the remaining elements such as holmium, erbium, thulium ytterbium and lutetium it is unfortunately true that their relatively low abundance coupled with high cost has tended to preclude their use in applications outside of the laboratory. 

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). 

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 ... 

Isotope abundances which are free from aU sources of bias are defined as absolute isotope abundances. The absolute isotope composition of elements can be measured by MC-TIMS and MC-ICP-MS via gravimetric synthetic mixtures or standard solutions from highly enriched isotopes, as demonstrated for neodymium," erbium and samarium, respectively. 

Erbium ranks about number 42 in abundance in Earth s crust. It is more common than bromine, uranium, tin, silver, and mercury. It occurs in many different rare earth minerals, naturally occurring lanthanoid mixtures. Some common sources of erbium are xenotime, fergusonite, gado-linite, and euxenite. 

Yttrium is one of the most abundant rare earth elements and its purification is easily accomplished. Yttrium fractions from a bromate series are freed from dysprosium, holmium, and erbium by fractional precipitation with ammonia, K2OO4, or NaNC>2. The latter is probably the most effective. Yttrium salts give no absorption lines ini the viable portion of the spectrum, consequently the removal of holmium and erbium is easily observed by the direct vision spectroscope. 

Rare earth ions have been paid much attention to for their partieular optical properties and magnetic properties. Rare earth compound have been widely used as laser materials, lumineseent materials, coloring agents of ceramics or glass and so on l The optical materials doped erbium ion have been widely investigated for this ion has abundant energy levels. The energy levels and... 

Despite all the technological applications and investigations of rare-earth YAG lasers, the optical spectra of some of the rare-earth ions in this host are of questionable quality and in some cases nonexistent. Only two rare-earth ions in YAG, neodymium and erbium, have been thoroughly investigated and reported. This is rather surprising when compared to lanthanum trifluoride (LaFa), for which Kaminskii reports only 16 lasers, although abundant excellent data exist (Camall et al., 1977) for all of the rare-earth ions in LaFs except terbium. 

Known rare-earth minerals were few gadolinite and ce-rite were extremely rare and the other minerals (there were about ten of them) could be likened, as regards their abundance, to museum pieces. Nevertheless, the era of new discoveries had come and the first sprouts appeared on the yttrium tree. Mosander s erbium remained controversial for a long time and only in 1878 did the Swiss scientist J. de Marignac separate a new element from erbium he named it ytterbium also after the village of Ytterby. 

The rare earth minerals are composed of scandium, yttrium, and the lanthanides. The lanthanides comprise a group of 15 elements that include lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. Cerium is the most abundant element in the rare earth group at 60 ppm, followed by yttrium at 33 ppm, lanthanum at 30 ppm, and neodymium at 28 ppm. Thulium and lutetium are the least abundant at 0.5 ppm. 

Besides triplet-triplet annihilation, a further process for achieving upconversion luminescence emission under continuous wave low-energy irradiation is based oti the use of lanthanide ions, most often erbium, holmium, and thulium (III) cations. In particular, a large variety of phosphors based on an inorganic host doped by lanthanide cations have been developed. The abundance of available states in these cations opens a large variety of paths for upconversion. As an example (Scheme 7.6), upconversion nanoparticles codoped with ytterbium and erbium cations exhibit a green emission due to the transitions from Hn/2 and respectively " Sn/2 excited states to the ground state as well as a red emission from the F9/2 state [10]. 

It surprises most people to learn that several of the so-called rare earth elements are not actually that rare compared to much more familiar elements. Neodymium, praseodymium, samarium, gadolinium, dysprosium, erbium, and ytterbium are all more abundant than more familiar elements like bromine, uranium, or tin. Europium, holmium, terbium, lutetium, and thulium are more abundant than iodine, silver, or mercury. Yet few people have even heard of most of the rare earths. The reason is that rare earths tend not to concentrate in large ore deposits in the way that better known metals do. Historically there have been fewer profits to be made from mining rare earth elements, and there have been fewer applications developed for them in industry. 

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