Erbium separation

Of the remaining 26 undiscovered elements between hydrogen and uranium, 11 were lanthanoids which Mendeleev s system was unable to characterize because of their great chemical similarity and the new numerological feature dictated by the filling of the 4f orbitals. Only cerium, terbium and erbium were established with certainty in 1871, and the others (except promethium, 1945) were separated and identified in the period 1879 -1907. The isolation of the (unpredicted) noble gases also occurred at this time (1894-8). 

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. 

Erbium - the atomic number is 68 and the chemical symbol is Er. The name derives from the Swedish town of Ytterby (about 3 miles from Stockholm), where the ore gadolinite (in which it was found) was first mined. It was discovered by the Swedish surgeon and chemist Carl-Gustav Mosander in 1843 in an yttrium sample. He separated the yttriiom into yttrium, a rose colored salt... 

A stone quarry near the town of Ytterby in Sweden produces a large number of rare-earth elements. Carl Gustaf Mosander (1797-1858) discovered several rare-earths, including the rare-earth mineral gadolinite in this quarry in 1843. He was able to separate gadolinite into three separate, but closely related, rare-earth minerals that he named yttria (which was colorless), erbia (yellow color), and terbia (rose-colored). From these minerals, Mosander identified two new rare-earth elements, terbium and erbium. The terbia that was found was really a compound of terbium terbium oxide (Tb O )... 

Dysprosium was first discovered in 1886 by the chemist, Paul-Emile Lecoq de Boisbaudran (1838-1912) as he analyzed a sample of the newly discovered erbium oxide (element 68). Boisbaudran was able to separate erbium oxide from a small sample of a new oxide of a metal. He identified this new element as element 66 on the periodic table and called it dispro-... 

In the 1800s chemists searched for new elements by fractionating the oxides of rare-earths. Carl Gustaf Mosander s experiments indicated that pure ceria ores were actually contaminated with oxides of lanthanum, a new element. Mosander also fractionated the oxides of yttria into two new elements, erbium and terbium. In 1878 J. Louis Soret (1827—1890) and Marc Delafontaine (1837-1911), through spectroscopic analysis, found evidence of the element holmium, but it was contaminated by the rare-earth dysprosia. Since they could not isolate it and were unable to separate holmium as a pure rare-earth, they did not receive credit for its discovery. 

Although erbium is magnetic at very low temperatures, it is antiferromagnetic and becomes a superconductor at temperatures near absolute zero. It is insoluble in water but soluble in acids. Its salts range from pink to red. Erbium and some of the other rare-earth elements are considered to be impurities in the minerals in which they are found. Small quantities of erbium can also be separated from several other rare-earths. 

It is found in ores such as monazite, gadohnite, and bastnasite. It was first separated into three elements in 1843 (yttria, erbia, and terbia). Erbium is also produced as a by-product of nuclear fission of uranium. 

Carl Gustaf Mosander, a Swedish chemist, successfully separated two rare-earths from a sample of lanthanum found in the mineral gadolinite. He then tried the same procedure with the rare-earth yttria. He was successful in separating this rare-earth into three separate rare-earths with similar names yttia, erbia, and terbia. For the next 50 years scientists confused these three elements because of their similar names and very similar chemical and physical properties. Erbia and terbia were switched around, and for some time the two rare-earths were mixed up. The confusion was settled ostensibly in 1877 when the chemistry profession had the final say in the matter. However, they also got it wrong. What we know today as erbium was originally terbium, and terbium was erbium. 

Erbium oxide was separated and obtained from the rare earth oxide, yttrea in 1842 by Mosander. Urbain and James independently separated this oxide from other rare earth oxide mixtures in 1905. The pure metal was produced by Klemm and Bommer in 1934 in powdered form. 

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). 

Soret and Delafontaine identified holmium in 1878 by examination of its spectrum. The following year, Cleve separated its oxide from Marignac s erbia, a mixture of erbium, holmium and thulium oxides. He named this element Holmium, after his native town Holmia (Stockholm). The metal was produced in 1934 by Klemm and Bommer. 

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 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). 

Cerous iodates and the iodates of the other rare earths form crystalline salts sparingly soluble in water, but readily soluble in cone, nitric acid, and in this respect differ from the ceric, zirconium, and thorium iodates, which are almost insoluble in nitric acid when an excess of a soluble iodate is present. It may also be noted that cerium alone of all the rare earth elements is oxidized to a higher valence by potassium bromate in nitric acid soln. The iodates of the rare earths are precipitated by adding an alkali iodate to the rare earth salts, and the fact that the rare earth iodates are soluble in nitric acid, and the solubility increases as the electro-positive character of the element increases, while thorium iodate is insoluble in nitric acid, allows the method to be used for the separation of these elements. Trihydrated erbium iodate, Er(I03)3.3H20, and trihydrated yttrium iodate, Yt(I03)3.3H20,... 

Erbium occurs in certain types of apatites, xenolime. and gadolinite. These minerals also are processed for their yttrium content as well as for other heavy Lanthanide elements. With liquid-liquid organic and solid-resin organic inn-exchange techniques, the separation of erbium from the other elements is favorable. 

Spectrum of the Glowing Oxide.—Neodymium oxide is one of the very few solids with a discontinuous spectrum. The spectrum which was known long before neodymium was separated from its fellow element praesodymium, was briefly described by Bunsen1 in 1864, who in the same communication mentions the discovery by Bahr2 of the similarly banded spectrum of erbium oxide. Thus far, however, no thorough-going study seems to have been made of this class of spectrum. 

Fig. 14. The separation of the RDF for the 1 M erbium(III) chloride solution in Fig. 13 into a RDF involving only the metal ions (upper curve) and a reduced RDF for the remaining nonmetal interactions (lower curve). Theoretical peaks for eight water molecules (1st coordination sphere) and 16 water molecules (2nd coordination sphere) are shown for comparison (upper curve).

More precise structural information can be obtained when a separation of interactions can be made. The RDFs for 2.9 M solutions of erbium(III) and yttrium(III) nitrate, which are isostructural (36), are... 

By using the intensity difference curve the light atom interactions can be eliminated and the RDF, including only interactions involving the metal ions, can be calculated. The results, referred to the erbium(III) solutions, are shown in Fig. 23 for three nitrate solutions of different compositions, including the 2.9 M solution illustrated in Fig. 22. The intramolecular N03 interactions together with all other nonmetal interactions are now eliminated and the first coordination peak appears as a separate peak. Its shape, however, depends on the composition of the solution, contrary to what was found for perchlorate solutions of similar compositions, and in comparison with these it is significantly broadened. For the 1 M solutions the difference is small but it becomes much more pronounced, when the concentration of nitrate ions is in-... 

Fig. 24. The RDF for solution B in Fig. 23, after elimination of nonmetal interactions (solid line) is analyzed by comparison with peaks calculated for a bidentate bonding of two nitrate ions to erbium(III). The lower half shows the separate peaks Er—0(H20) at 2.32 A, Er—0(N03) and Er—N at 2.45 A and 2.8 A, Er—03 at 4.1 A, and Er—H20 at 4.6 A. In the upper half of the figure the sum of the individual peaks, indicated by dots, is compared with the experimental RDF.

Fig. 27. RDFs for 1 M erbium(III) nitrate and chloride solutions in DMSO (solid lines) with nonmetal interactions eliminated. DMSO is coordinated over oxygen with an average Er—O—S angle of abut 130°. Nitrate is coordinated as a bidentate ligand. The Er—Cl distance for chloride in the first coordination sphere is 2.57 A. Theoretical values calculated for Er(N03)15(dmso)59 in the nitrate solution and ErCl13(dmso)5 2 in the chloride solution are marked by dots. The contributions from the coordinated anions (N03 or Cl ) are separately shown as dotted lines.

They are but sparingly soluble in water. In dilute hydrochloric acid their solubilities vary somewhat, the yttrium salt being some three times as soluble as that of erbium, a fact that enables the two metals to be separated in this way.3... 

Erbium(III) with f11 configuration has 17 multiplet terms with 41 levels due to spin-orbit coupling. The J energy levels are more separated than in Nd3+. The energy level diagram... 

Four rare-earth elements (yttrium, ytterbium, erbium, and terbium) have been named in honor of this village. A year later, the Swedish chemist Lars Fredrik Nilson (1840-1899), discovered another element in "erbia" and he named it scandium (Sc) in honor of Scandinavia. At the same time, Nilson s compatriot, the geologist and chemist Per Theodor Cleve (1840-1905) succeeded in resolving the "erbia" earths yet another step further, when he separated it into three components erbium, "holmium" (Flo) and thulium (Tm). The name "holmium" refers to Stockholm (Qeve s native city) and had been independently discovered by the Swiss chemists Marc Dela-fontame (1838-1911) and Jacques-Louis Soret (1827-1890), who had coined the metal element X on the basis of its absorption spectrum. 

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