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Topic: Lanthanide

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In the News (Mon 19 Aug 19)

  Lanthanide - Wikipedia, the free encyclopedia
The lanthanide series comprises the 15 rare earth elements from lanthanum to lutetium on the periodic table, with atomic numbers 57 through 71.
Lanthanides are chemically similar to each other, to scandium and yttrium, and to the actinides.
The lanthanides are typically placed below the main body of the periodic table in the manner of a footnote.
en.wikipedia.org /wiki/Lanthanide   (273 words)

 Chemiluminescence of Lanthanide Beta-Diketonate - 1,2-Dioxetane System
1) Excitation of chemiluminescence of weakly luminescent lanthanide ions, e.g.
The chemiluminescence of lanthanide ions was almost exclusively studied by using europium and terbium compounds that posess highly efficient visible luminescence (red and green respectively).
Coordination-unsaturated lanthanide beta-diketonates efficiently catalyze the decomposition of 1,2-dioxetanes through the formation of complex in which the peroxide coordinates to lanthanide ion by the oxygen atoms.
lanthanides.tripod.com /ln-cl.html   (1000 words)

 United States Patent Application: 0040175949
The lanthanide-containing metal oxide material can be a lanthanide oxide, a doped lanthanide oxide, a lanthanide-doped metal oxide, a lanthanide perovskite, or any other suitable lanthanide-containing mixed metal oxide material, in particular those used as solid electrode and solid electrolyte materials in gas sensor and fuel cell devices.
The lanthanide metal can be any element selected from the lanthanide series including elements selected from the group consisting of yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and combinations thereof.
When the dopant is a lanthanide element, the dopant typically is selected from the group consisting of yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and combinations thereof.
appft1.uspto.gov /netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=/netahtml/PTO/search-adv.html&r=1&f=G&l=50&d=PG01&p=1&S1=20040175949&OS=20040175949&RS=20040175949   (3907 words)

 lanthanide series on Encyclopedia.com
Members of the series are often called lanthanides, although lanthanum (atomic number 57) is not always considered a member of the series.
The series always includes the 14 elements with atomic numbers 58 through 71, which are (in order of increasing atomic number) cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.
The lanthanides have similiar sizes so that any given compound of the rare earths is likely to crystallize with the same structure as any other rare earth; however, the lattice parameters become smaller and the crystal denser as compounds proceed across the series.
www.encyclopedia.com /html/l1/lanthani.asp   (464 words)

 Lanthanide   (Site not responding. Last check: 2007-09-20)
Yb The lanthanide series is the 14 rare earth chemical elements which lie between lanthanum and ytterbium on the periodic table.
Lanthanides are elements in which the f orbitals are partly or completely filled, while the outermost p and d orbitals are empty.
Since the f orbitals do not have as much effect on chemistry as the s, p, and d orbitals, lanthanide series elements are chemically similar to each other.
www.yotor.com /wiki/en/la/Lanthanide.htm   (134 words)

 United States Patent: 6,790,791   (Site not responding. Last check: 2007-09-20)
The doping of the TiO.sub.x layer with a lanthanide occurs as a substitution of a lanthanide atom for a Ti atom.
Evaporating the lanthanide source is begun substantially concurrent with evaporating TiO.sub.2, while bombarding the body region with Ar ions shortly after the evaporation of the TiO.sub.2 has begun, forming a gate dielectric 140 containing lanthanide doped TiO.sub.x on the body region.
Lanthanide doped TiO.sub.x films formed by ion assisted electron beam evaporation can be amorphous and possess smooth surfaces and high packing densities, which limits the occurrence of adsorbed water in the films.
web.engr.oregonstate.edu /~flf/6790791.html   (11893 words)

 World Intellectual Property Organization   (Site not responding. Last check: 2007-09-20)
Lanthanide oxides is understood to include oxides of one or more of the rare earth elements of the lanthanide series according to the Periodic Table of Elements, which includes elements 57-71.
Thus, lanthanide oxide particle levels must be kept low on glass substrates to achieve the corrosion resistance and smooth surface necessary for use of glass substrates in computer disk drives.
In accordance with the principles of the present invention, the residual lanthanide oxide particles are removed by immersing the substrate in an acid bath of nitric acid, hydrogen peroxide and an organic acid having a carboxylic acid group.
www.wipo.int /ipdl/IPDL-CIMAGES/view/pct/getbykey5?KEY=01/87790.011122&ELEMENT_SET=DECL   (5837 words)

 United States Patent Application: 0050194885
The device of claim 22, wherein the color of the light source converted by the transparent polymer is dependent on the type of light source and the mole ratio X:Y=3-x:2+2x of A and B in the phosphor, determined by x.
The red luminescence emitted by the phosphor increases in intensity as the proportion of organic phosphine oxide, one of the ligands in a lanthanide chelate, increases.
Although not all lanthanide ion solutions are dissolved in acid, the dissolution of the salt of these rare earth metals, usually nitrates or chlorides, in deionised water would usually give raise to an acidic environment in view of the chloride ions and the nitrate ions in the same solution of the dissolved salts.
appft1.uspto.gov /netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=/netahtml/PTO/search-adv.html&r=1&f=G&l=50&d=PG01&p=1&S1=20020158565&OS=20020158565&RS=   (3599 words)

 CT 2/99: Lanthanide triflates as unique Lewis acids
Lanthanide trifluoromethanesulfonates (triflates) are unique Lewis acids that are currently of great research interest.
As is often observed, the radii of the lanthanide ions played an important role in the catalytic process.
Whereas it is troublesome to remove and recycle the soluble lanthanides in the former case, the separation and recycling of the supported lanthanides require only simple filtration.
pubs.acs.org /hotartcl/chemtech/99/feb/lanth.html   (1688 words)

 Bioaccessibility of Lanthanide Metals   (Site not responding. Last check: 2007-09-20)
Lanthanide metals (also known as rare earths) are a group of 15 elements that are used in electronic, automotive, environmental, and medical technologies.
A key factor in estimating human and biotic exposures was the bioaccessibility of lanthanide metals.
Site-specific exposures to lanthanide metals were estimated using the proportion of the total concentration that is soluble under simulated gastrointestinal tract conditions (including stomach pH, mixing, and emptying rates).
www.riskworld.com /Abstract/2002/SRAam02/ab02aa264.htm   (230 words)

Lanthanides are grouped because of their chemical similarities (most are trivalent, but some can be divalent or tetravalent), their properties differing only slightly with atomic number.
Lanthanides were called rare earths originally because they were not widespread and were difficult to identify and separate from their ores by their discoverers.
The series is set out in a band in the periodic table of the elements, as are the actinides.
www.tiscali.co.uk /reference/encyclopaedia/hutchinson/m0010050.html   (185 words)

 National Synchrotron Light Source
The feasibility of using phosphate to enhance radionuclide immobilization on mineral surfaces was examined using trivalent lanthanide ions as chemical analogues of actinide radionuclides.
In this study, trivalent lanthanide ions (Eu, Gd, and Dy serve as chemical analogues of trivalent actinides to explore the sorption chemistry of actinide ions (Ac) on mineral surfaces as affected by phosphate, a ubiquitous oxyanion found on all oxide mineral surfaces in nature.
The structure of the sorbed lanthanide was determined by x-ray absorption spectroscopy (beamlines X23B and X10C at the National Synchrotron Light Source, Brookhaven National Laboratory), as well as by magnetic susceptibility measurements (Institute for Rock Magnetism at University of Minnesota and Kansas State University) and electron paramagnetic resonance (EPR) spectroscopy (EMSL, Pacific Northwest National Laboratory).
www.nsls.bnl.gov /newsroom/science/2003/08-Yoon.htm   (577 words)

 Physical Properties of Melts, Magmas, and Lavas I Posters - Volcanology, Geochemistry, Petrology [V]
Lanthanides are of great interest in igneous petrology as trace indicators of magmatic processes that control the origin and evolution of igneous rocks.
A key to the petrogenetic modelling of magmatic processes and to determine the phase diagrams of lanthanide host phases is the accurate determination of the physico-chemical and thermodynamic properties of lanthanide-containing materials, such as the volumetric properties of lanthanide-bearing silicate melts.
Comparison between the partial molar volumes of lanthanide sesquioxides obtained in this study and the molar volumes of molten lanthanide sesquioxides given in the literature raise the possibility however that this ideality is not maintained along the entire Na-disilicate - lanthanide sesquioxide pseudo-binary joins.
www.agu.org /meetings/fm04/fm04-sessions/fm04_V41A.html   (6599 words)

 Photochemistry and Photobiology: Sensitization of lanthanides by nonnatural amino acids
In such cases, a chelated lanthanide that is associated with one partner sensitizes an acceptor on a complementary partner when these species are within the typical Forster distance range of 3 to 9 nm (3).
Efficient sensitization of the lanthanide by an organic chromophore requires suitable overlap of the donor emission band with the excitation band of the metal ion, efficient coordination of the lanthanide so that a minimum number of water molecules coordinate to the metal ion, and a chromophore-lanthanide distance of 10 A or less (5).
Upon chelation of a lanthanide, the distance and relative orientation between the chromophore and the ion are fixed; thus, perturbations of transfer efficiency owing to changes in these parameters are eliminated, simplifying analysis of the results.
www.findarticles.com /p/articles/mi_qa3931/is_200202/ai_n9038794   (1138 words)

 Demonstration of the Feasibility of Recovering Americium and Curium Isotopes from a Lanthanide Borosilicate Glass
The lanthanide oxides in the glass, as surrogates for Am/Cm, were successfully leached from the simulated glass using 15.7M nitric acid [4].
This small shortfall in recovery was found to be statistically insignificant based on the variance in the measured concentrations used to calculate the masses of the recovered lanthanides and the total lanthanides in the glass.
For dissolution tests in which the measured lanthanide recoveries were slightly less than 98%, uncertainties associated in the measured glass compositions and the dissolving solution analyses accounted for the difference.
sti.srs.gov /fulltext/ms2001451/ms2001451.html   (2487 words)

 Low environmental impact surface pretreatments. Lanthanide elements based systems
Lanthanide salts as corrosion inhibitors of aluminium alloys
Nevertheless, because of their high both toxicity and environmental impact, an intensive research effort is being undertaken to look for the replacement of chromate by more environmentally friendly compounds.
In a variety of practical applications in which lanthanide compounds are used, it has been shown that using formulations based on mixtures of lanthanide elements can enhance the performance of pure compounds.
www.uca.es /grup-invest/corrosion/research/lanthanide/lanthanide.htm   (598 words)

 Lanthanide Silicates   (Site not responding. Last check: 2007-09-20)
early transition metal, lanthanide and actinide species has been shown to have great potential, and catalysts derived from such metals have been shown to have activities equalling or surpassing those of more conventional platinum group metal catalysts.
Despite the great oxophilicity of the f-block metals there has been just one report of a lanthanide siloxane, and organo-lanthanide chemistry in an O-donor environment is almost unknown.
We have prepared monomeric lanthanide silsesquioxane complexes using PMDTA as a face capping ligand as shown above.
int.ch.liv.ac.uk /Lanthanide/Lanthanide_Silicates.html   (173 words)

 ISIC - Jean-Claude Bünzli   (Site not responding. Last check: 2007-09-20)
Professor J.-C.G. Bünzli is a physical-inorganic and analytical chemist by training and an active researcher in the field of co-ordination and supramolecular chemistry of the lanthanide ions.
One strategy that we are pursuing in collaboration with Professor C. Piguet (University of Geneva) is the design of compartmental pentadentate or hexadentate ligands leading to the simultaneous complexation of one 3d and one 4f metla ions or of two different 4f ions.
Lanthanide triple helical complexes with a chiral ligand derived from 2,6-pyridinedicarboxalic acid.
isic.epfl.ch /bunzli_e.htm   (2679 words)

 Chem4Kids.com: Elements & Periodic Table: Lanthanide Series
One of those rows is called the Lanthanide series.
There are a bunch of names that you may hear that describe these 15 elements.
No matter what you choose everyone will know what you mean if you say Lanthanide.
www.chem4kids.com /files/elem_lanthanide.html   (145 words)

 W&L Journal of Science
The chemistry of the lanthanide elements has come under increasing scrutiny with the recent discovery that these compounds can serve as biological probes, artificial ribonucleases, MRI contrast agents, and magnetic materials.
For instance, because simple ionic lanthanide species exhibit significant toxicity, complexes to be used as biological probes, or especially as MRI contrast agents, must have a high binding constant for the lanthanide ion in question.
General procedure for inserting lanthanide ions into the macrocycle to yield monoanionic products whose axial coordination would be a subject of study.
journalofscience.wlu.edu /archive/winter1999/articles/chemistry/uffelman.htm   (995 words)

 University of Virginia Department of Chemistry
The lanthanide elements exhibit remarkably diverse optical and magnetic properties across the lanthanide series (from cerium to ytterbium).
These properties may be understood largely in terms of the electronic states split out of the 4fN (N=1-13) electronic configuration, and when a lanthanide ion resides in a ligand or crystalline environment these properties depend on the details of the lanthanide-ligand (or crystal) interactions.
Systematic characterizations of these parameters yield information essential to the rational design of lanthanide systems with pre-specified optical and magnetic properties, and they are necessary in selecting lanthanide ions to be used as spectroscopic probes of biomolecular structure and function.
www.virginia.edu /chem/people/faculty/richardson   (474 words)

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