• Home
  • rare earth trivalent

a trivalent metallic element of the rare earth group ...

Answers for a-trivalent-metallic-element-of-the-rare-earth-group. crossword clue. Search for crossword clues found in the Daily Celebrity, NY Times, Daily Mirror, Telegraph and major publications. Find clues for a-trivalent-metallic-element-of-the-rare-earth-group. or most any crossword answer or clues for crossword answers.

Ytterbium | Definition of Ytterbium by Merriam-Webster

Ytterbium definition is - a soft metallic element of the rare-earth group that occurs especially with other rare earth elements in minerals and that has few commercial uses.

Synthesis and Luminescence Properties of Trivalent Rare ...

ABSTRACT The phosphors of calcium stannate activated with individual trivalent rare-earth element (REE) ions (Neodymium III, Europium III, Terbium III, Dysprosium III, and Samarium III) were synthesized by high-temperature solid-state reaction (SSR), and their characterization and luminescent properties were investigated. The crystal structures and morphologies of the resultant materials were ...

Optical Properties of Trivalent Praseodymium Doped in a ...

Trivalent praseodymium ion Pr 3+ has long been considered a serious contender for laser applications. The Judd-Ofelt 1,2 theory has been one of the most successful theories in estimating the magnitude of the forced electric dipole transitions of rare-earth ions in a large variety of laser host media. Also, there has been significant interest in ...

Red, green, and blue upconversion luminescence of ...

Trivalent-rare-earth ion-doped Y2O3 nanocrystals have been synthesized, and their photoluminescence properties have been studied under 980 nm laser diode excitation. The crystallite size estimated by x-ray diffractometry and scanning electron microscopy was about 30–40 nm. In Yb3+ and Tm3+ codoped Y2O3 nanocrystals, the bright blue emissions near 450 and 480 nm have been noticeable due to ...

Theoretical Study of pKa Values for Trivalent Rare-Earth ...

Molecular acidity of trivalent rare-earth metal cations in aqueous solution is an important factor dedicated to the efficiency of their extraction and separation processes. In this work, the aqueous acidity of these metal ions has been quantitatively investigated using a few theoretical approaches. Our computational results expressed in terms of pKa values agree well with the tetrad effect of ...

Homoleptic Trivalent Tris(alkyl) Rare Earth Compounds ...

A series of homoleptic rare-earth silazido compounds and their silica-grafted derivatives were prepared to compare spectroscopic and catalytic features under homogeneous and interfacial conditions.

RARE EARTH ELEMENTS - periodni.com

The rare earth elements are often described as being a 'light-group rare earth element' (LREE) or 'heavy-group rare earth element' (HREE). The definition of a LREE and HREE is based on the electron configuration of each rare-earth element. The LREE are defined as lanthanum, atomic number 57 through gadolinium, atomic number 64.

The Smaller the Better: Hosting Trivalent Rare-Earth ...

Jun 14, 2018· The most striking difference between the trivalent rare-earth cations and their alkali and alkaline-earth peers is the presence of localized 4f electrons. Placing trivalent rare-earth cations inside fullerene molecules or in between blocks of intermetallics has given rise to a plethora of fascinating properties and materials.

Trivalent rare‐earth activated hexagonal lanthanum ...

The LaF 3 nanocrystals through a facile hydrothermal route with hexagonal structures have been synthesized via doping of trivalent rare earth (RE 3+) ions – RE = Tb, Sm, Dy and Tm – with rod‐like and perforated morphologies using NH 4 F as fluorine precursor. Hexagonal phase formation was confirmed by powder X‐ray diffraction. The crystalline sizes were calculated by the Scherrer ...

Solubility Products of the Trivalent Rare-Earth Phosphates

The precipitation sequence of different REEs is in agreement with the reported solubility products for trivalent rare earth elements phosphates (Firsching and Brune, 1991) thus higher ...

Stability Constant of Nadifloxacin with Trivalent Rare ...

Stability Constant of Nadifloxacin with Trivalent Rare Earth Metal in Aqueous Media: A pH-Metric Study Megha Rai1, Jameel Pathan2, HB Nagre3 and DD Kayande4 1Department of Chemistry, Dr. Rafiq Zakaria College for Women, Aurangabad, India 2Department of Chemistry, Sant Ramdas College Ghansawngi, Jalna, India

Phase equilibria in systems involving the rare-earth ...

Trivalent Rare-Earth Ions R. S. Roth and S. J. Schneider (April 5, 1960) The polymorphic relatioll ships of the pure rare-carlh oxides have been rei nvestigated using X-ray diffraction methods for identification of phases. The oxides of the trivalent rare earth ions crystallize in t hree different types: Art B, and C.

Rare Earth Elements and Intelligent Design | Evolution News

Mar 05, 2019· Rare Earths and Rare Earth. In 2000, Ward and Brownlee published a controversial book, Rare Earth: Why Complex Life Is Uncommon in the Universe. At a time when most scientists assumed there must be millions of complex civilizations in the Milky Way alone, the authors rained on their parade, arguing that the requirements for complex life are so ...

Interactions between trivalent rare earth oxides and mixed ...

Jan 01, 2016· Interactions between trivalent rare earth oxides and mixed [Hbet][Tf 2 N]:H 2 O systems in the development of a one-step process for the separation of light from heavy rare earth elements

ENERGIES OF RARE-EARTH ION STATES RELATIVE TO HOST …

ENERGIES OF RARE-EARTH ION STATES RELATIVE TO HOST BANDS IN OPTICAL MATERIALS FROM ELECTRON PHOTOEMISSION SPECTROSCOPY by Charles Warren Thiel ... trivalent rare-earth ions.....131 . x LIST OF FIGURES – CONTINUED Figure Page 3.2 Variation of experimental spin-orbit parameters with valence state for ...

Synthesis and structural diversity of trivalent rare-earth ...

Our interest in trivalent diiso-propylamide rare-earth metal complexes was also triggered by our recent finding that homoleptic Ce(NiPr 2) 4 is a useful pre-cursor in Ce(IV) chemistry.23 On the basis of a few literature reports it was clear that the outcome of any salt metathesis

Praseodymium | Definition of Praseodymium at Dictionary.com

Praseodymium definition, a rare-earth, metallic, trivalent element, named from its green salts. Symbol: Pr; atomic weight: 140.91; atomic number: 59; specific gravity ...

Rare Earths – Hastings Technology Metals Limited

In addition to being the world's largest producer of rare earth materials, China is also the dominant consumer followed by Japan and the United States. By 2010 China controlled about 95% of the world's rare earth production and prices for many rare earth oxides but prices had risen over 500% in …

Article TheSmallertheBetter:HostingTrivalent Rare- Earth ...

trivalent rare-earth cations inside fullerene molecules or in between blocks of intermetallics has given rise to a plethora of fascinating properties and mate-rials. A long-sought-after yet undiscovered material is a semiconducting com-pound with rare-earth cations situated inside the oversized polyhedral cages

Rare Earth Elements - Science Notes and Projects

Scandium forms a trivalent cation, like the other rare earth elements, but it does not meet the electron configuration criterion for an LREE and does not share enough chemical properties with the HREE to be considered one of them. Uses of the Rare Earth Elements. The rare earth metals are used in a variety of materials and products, including:

US3574130A - Europium activated rare earth phosphors ...

an improved process for the manufacture of europiumactivated rare earth oxide phosphors, europium-activated rare earth phosphors derived from rare earth oxides and mixtures thereof and the improved phosphors are disclosed. the improvement comprises controlling the brightness of the phosphor by incorporating a controlled amount of cerium into the europium-activated rare earth oxide at the time ...

Homoleptic Trivalent Tris(alkyl) Rare Earth Compounds ...

Learn more about these metrics Article Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days. The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online.

Upconversion-pumped luminescence efficiency of rare-earth ...

Upconversion-pumped luminescence efficiency of rare-earth-doped hosts sensitized with trivalent ytterbium Ralph H. Page, Kathleen I. Schaffers, Phillip A. Waide, John B. Tassano, Stephen A. Payne, William F. Krupke, and William K. Bischel

Light Rare Earth Elements (LREE) - ThoughtCo

Mar 10, 2019· The light rare earth elements, light-group rare earths, or LREE are a subset of the lanthanide series of the rare earth elements, which are themselves a special set of transition metals.Like other metals, the light rare earths have a shiny metallic appearance.

RP Photonics Encyclopedia - rare-earth-doped gain media ...

Note that the rare earth elements include all the lanthanides except for the radioactive prometium, plus scandium and yttrium. All the laser-active rare earth ions are actually lanthanides. Therefore, lasers based on rare-earth-doped gain media are sometimes called lanthanide lasers. Overview on Rare-earth …

Rare-earth element - Electronic structure and ionic radius ...

Rare-earth element - Electronic structure and ionic radius: The chemical, metallurgical, and physical behaviours of the rare earths are governed by the electron configuration of these elements. In general, these elements are trivalent, R3+, but several of them have other valences. The number of 4f electrons of each lanthanide is given in the table of the number of 4f electrons and ionic radii ...

Trivalent Metal Compound (e.g., Iron Oxide, Chromium Oxide ...

Jun 27, 2012· Search for Trivalent Metal Compound (e.g., Iron Oxide, Chromium Oxide, Trivalent Rare Earth Oxide, Etc.) Containing Patents and Patent Applications (Class 501/126) Filed with the USPTO

Europium - Wikipedia

The second large source for rare-earth elements between 1965 and its closure in the late 1990s was the Mountain Pass rare earth mine. The bastnäsite mined there is especially rich in the light rare-earth elements (La-Gd, Sc, and Y) and contains only 0.1% of europium. Another large source for rare-earth elements is the loparite found on the ...

Complexation of trivalent rare earth elements (Ce, Eu, Gd ...

Request PDF on ResearchGate | Complexation of trivalent rare earth elements (Ce, Eu, Gd, Tb, Yb) by carbonate ions | Carbonate stability constants for five rare earth elements (Ce[sup 3+], Eu[sup ...

Spectroscopy of divalent rare earth ions in fluoride crystals

the trivalent state is well-favored [1]. The negative or close to zero energy difference indicates that divalent state is more stable. It was observed for Eu, Yb and Sm ions. However, in crystals a certain fraction of any of the trivalent rare-earth ions can be reduced to the 2+ oxidation state by ionizing

Rare-earth element - Properties of the metals | Britannica.com

The electrical resistivities of the rare-earth metals vary from 25 to 131 microohms-cm (μΩ- cm), which fall into the middle of the electrical resistance values of the metallic elements. Most trivalent rare-earth metals have values at room temperature ranging from about 60 to 90 μΩ-cm.