Carbon rare earth elements

Laser isotope separation techniques have been demonstrated for many elements, including hydrogen, boron, carbon, nitrogen, oxygen, sHicon, sulfur, chlorine, titanium, selenium, bromine, molybdenum, barium, osmium, mercury, and some of the rare-earth elements. The most significant separation involves uranium, separating uranium-235 [15117-96-1], from uranium-238 [7440-61-1], (see Uranium and uranium compounds). The... 

SWCNT is synthesized by co-evaporation of carbon and catalyst (mostly metals) in arc discharge. In early time, Fe [3], Co [4], Ni [8, 10] or rare-earth element [10] was employed as the catalyst (see Fig. 7). In these syntheses, however, the yield of SWCNT was quite low. In the improved method, the catalyst consisting of more than one element such as Co-Pt [12,13] or Ni-Y [14] is used to increase the yield of SWCNT (e.g., more than 75 % with Ni-Y [14]). 

Superconductivity has also been discovered in rather exotic materials, including the following Buckminsterfullerene (Cgo) doped with ICI Carbon nanotubes (superconductivity in just one direction) Nickel borocarbides, which contain Ni2 B2 layers alternating with R C sheets, where R is a rare earth element such as Er and organic superconductors that contain planar organic cations and oxoanions. Chemists and physicists continue to study these and other families of superconductors. 

Lanthanum is a naturally occurring trivalent rare earth element (atomic number 57). Lanthanum carbonate quickly dissociates in the acidic environment of the stomach, where the lanthanum ion binds to dietary phosphorus, forming an insoluble compound that is excreted in the feces. Lanthanum has been shown to remove more than 97% of dietary phosphorus... 

Trace elements and rare-earth elements (REEs) of the same calcite samples used for the stable isotope analysis have significantly lower concentration of REE as well as most trace elements relative to typical carbonatites. The total REE contents of the Ulsan carbonates range from 3 to 17 ppm, which are much lower than any igneous rocks and even lower than those of some sedimentary rocks. REE and trace-element abundances may have changed sufficiently due to alteration, thus, affecting petrogenetic... 

Sholkovitz ER, Elderfield H, Szymczak R, Casey K (1999) Island weathering riverine sources of rare earth elements to the western Pacific Ocean. Marine Chem 68 39-57 Skulan JL, Beard BL, Johnson CM (2002) Kinetic and equilibrium Fe isotope fractionation between aqueous Fe(III) and hematite. Geochim Cosmochim Acta 66 2995-3015 Sumner DY (1997) Carbonate precipitation and oxygen stratification in Late Archean seawater as deduced from facies and stratigraphy of the Gamohaan and Frisco Formations, Transvaal Supergroup, South Africa. Am J Sci 297 455-487... 

The third major invention for the use of the rare earth elements was the addition of rare earth fluoride as a wick in arc light carbons which, at that time, were used for a wide range of lighting purposes and later also for cinema production and for search lights. This use of rare earth compounds is based on the intensive arc light developed by Beck in Germany in 1910. 

The first applications of the rare earth elements / as already mentioned, were in the optical field, namely the Auer incandescent mantles and the arc light carbons. In 1964/65 as a result of the work of Levine and Palilla the use of the truly rare and therefore expensive europium together with yttrium made a major leap forward for the rare earth industry as red phosfdiors in color TV screens. Due to the strong and sharp emission line of europium at 610 A, without a yellow component, viiich is... 

It has been found by Utsumi(1985a,b) that in J-type carbon stars of C4-5 and WZ Cas(C9,2J Li), abundances of s-process elements with respect to Fe are nearly normal, while in normal carbon stars of C5-8, heavy metals are overabundant by factors of 10-100, and rare-earth elements are overabundant by a factor of about 10. 

Liu, X. and Byrne, R.H. (1998) Comprehensive investigation of yttrium and rare earth element complexation by carbonate ions using ICP-mass spectrometry. J. Sol. Chem., 27, 801-813. 

The sesquioxides M2O3 are the stable oxides for all rare-earth elements except Ce, Pr, and Tb, and are the final product of calcination of many salts such as oxalates, carbonates, and nitrates. The sesquioxides M2O3 adopt three structural types ... 

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