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Europium is a chemical element with the symbol Eu and atomic number 63. Europium is the most reactive lanthanide by far, having to be stored under an inert fluid to protect it from atmospheric oxygen or moisture. Europium is also the softest lanthanide, as it can be dented with a fingernail and easily cut with a knife. When oxidation is removed a shiny-white metal is visible. Europium was isolated in 1901 and is named after the continent of Europe. Being a typical member of the lanthanide series, europium usually assumes the oxidation state +3, but the oxidation state +2 is also common. All europium compounds with oxidation state +2 are slightly reducing. Europium has no significant biological role and is relatively non-toxic as compared to other heavy metals. Most applications of europium exploit the phosphorescence of europium compounds. Europium is one of the rarest of the rare-earth elements on Earth.
The lanthanide or lanthanoid series of chemical elements comprises the 15 metallic chemical elements with atomic numbers 57–71, from lanthanum through lutetium. These elements, along with the chemically similar elements scandium and yttrium, are often collectively known as the rare-earth elements or rare-earth metals.
In chemistry, a hydride is formally the anion of hydrogen, H−. The term is applied loosely. At one extreme, all compounds containing covalently bound H atoms are called hydrides: water (H2O) is a hydride of oxygen, ammonia is a hydride of nitrogen, etc. For inorganic chemists, hydrides refer to compounds and ions in which hydrogen is covalently attached to a less electronegative element. In such cases, the H centre has nucleophilic character, which contrasts with the protic character of acids. The hydride anion is very rarely observed.
Diborane(6), generally known as diborane, is the chemical compound consisting of boron and hydrogen with the formula B2H6. It is a toxic, volatile, colorless and pyrophoric gas with a repulsively sweet odor. Synonyms include boroethane, boron hydride, and diboron hexahydride. Diborane is a key boron compound with a variety of applications. It has attracted wide attention for its electronic structure. Its derivatives are useful reagents.
In chemistry, a dangling bond is an unsatisfied valence on an immobilized atom. An atom with a dangling bond is also referred to as an immobilized free radical or an immobilized radical, a reference to its structural and chemical similarity to a free radical.
Germane is the chemical compound with the formula GeH4, and the germanium analogue of methane. It is the simplest germanium hydride and one of the most useful compounds of germanium. Like the related compounds silane and methane, germane is tetrahedral. It burns in air to produce GeO2 and water. Germane is a group 14 hydride.
Aluminium hydride (also known as alane or alumane) is an inorganic compound with the formula AlH3. It presents as a white solid and may be tinted grey with decreasing particle size and impurity levels. Depending upon synthesis conditions, the surface of the alane may be passivated with a thin layer of aluminum oxide and/or hydroxide. Alane and its derivatives are used as reducing agents in organic synthesis.
Metal–organic frameworks (MOFs) are a class of compounds consisting of metal ions or clusters coordinated to organic ligands to form one-, two-, or three-dimensional structures. They are a subclass of coordination polymers, with the special feature that they are often porous. The organic ligands included are sometimes referred to as "struts" or "linkers", one example being 1,4-benzenedicarboxylic acid (BDC).
The helium hydride ion or hydridohelium(1+) ion or helonium is a cation (positively charged ion) with chemical formula HeH+. It consists of a helium atom bonded to a hydrogen atom, with one electron removed. It can also be viewed as protonated helium. It is the lightest heteronuclear ion, and is believed to be the first compound formed in the Universe after the Big Bang.
Molecule-based magnets (MBMs) or molecular magnets are a class of materials capable of displaying ferromagnetism and other more complex magnetic phenomena. This class expands the materials properties typically associated with magnets to include low density, transparency, electrical insulation, and low-temperature fabrication, as well as combine magnetic ordering with other properties such as photoresponsiveness. Essentially all of the common magnetic phenomena associated with conventional transition-metal magnets and rare-earth magnets can be found in molecule-based magnets. Prior to 2011, MBMs were seen to exhibit "magnetic ordering with Curie temperature (Tc) exceeding room temperature".
Binary compounds of hydrogen are binary chemical compounds containing just hydrogen and one other chemical element. By convention all binary hydrogen compounds are called hydrides even when the hydrogen atom in it is not an anion. These hydrogen compounds can be grouped into several types.
Europium (II) sulfide is the inorganic compound with the chemical formula EuS. It is a black, air-stable powder. Europium possesses an oxidation state of +II in europium sulfide, whereas the lanthanides exhibit a typical oxidation state of +III. Its Curie temperature (Tc) is 16.6 K. Below this temperature EuS behaves like a ferromagnetic compound, and above it exhibits simple paramagnetic properties. EuS is stable up to 500 °C in air, when it begins to show signs of oxidation. In an inert environment it decomposes at 1470 °C.
Hydrogen chalcogenides are binary compounds of hydrogen with chalcogen atoms. Water, the first chemical compound in this series, contains one oxygen atom and two hydrogen atoms, and is the most common compound on the Earth's surface.
An yttrium compound is a chemical compound containing yttrium. Among these compounds, yttrium generally has a +3 valence. The solubility properties of yttrium compounds are similar to those of the lanthanides. For example oxalates and carbonates are hardly soluble in water, but soluble in excess oxalate or carbonate solutions as complexes are formed. Sulfates and double sulfates are generally soluble. They resemble the "yttrium group" of heavy lanthanide elements.
An oxyhydride is a mixed anion compound containing both oxide O2− and hydride ions H−. These compounds may be unexpected as the hydrogen and oxygen could be expected to react to form water. But if the metals making up the anions are electropositive enough, and the conditions are reducing enough, solid materials can be made that combine hydrogen and oxygen in the negative ion role.
A hydridonitride is a chemical compound that contains hydride and nitride ions in a single phase. These inorganic compounds are distinct from inorganic amides and imides as the hydrogen does not share a bond with nitrogen, and contain a larger proportion of metals.
Europium dichloride is an inorganic compound with a chemical formula EuCl2. When it is irradiated by ultraviolet light, it has bright blue fluorescence.
Ytterbium hydride is the hydride of ytterbium with the chemical formula YbH2. In this compound, the ytterbium atom has an oxidation state of +2 and the hydrogen atoms have an oxidation state of -1. Its resistivity at room temperature is 107 Ω·cm. Ytterbium hydride has a high thermostability.
Europium(III) hydroxide is an inorganic compound with a chemical formula Eu(OH)3.
Europium(II) oxide (EuO) is a chemical compound which is one of the oxides of europium. In addition to europium(II) oxide, there is also europium(III) oxide and the mixed valence europium(II,III) oxide.
References
- ↑ SciFinder
- 1 2 Rybak, Jens-Christoph; Hailmann, Michael; Matthes, Philipp R.; Zurawski, Alexander; Nitsch, Jörn; Steffen, Andreas; Heck, Joachim G.; Feldmann, Claus; Götzendörfer, Stefan; Meinhardt, Jürgen; Sextl, Gerhard; Kohlmann, Holger; Sedlmaier, Stefan J.; Schnick, Wolfgang; Müller-Buschbaum, Klaus (29 April 2013). "Metal–Organic Framework Luminescence in the Yellow Gap by Codoping of the Homoleptic Imidazolate ∞3[Ba(Im)2] with Divalent Europium". Journal of the American Chemical Society. 135 (18): 6896–6902. doi:10.1021/ja3121718. PMID 23581546.
- ↑ Matsuoka, T.; Fujihisa, H.; Hirao, N.; Ohishi, Y.; Mitsui, T.; Masuda, R.; Seto, M.; Yoda, Y.; Shimizu, K.; Machida, A.; Aoki, K. (5 July 2011). "Structural and valence changes of europium hydride induced by application of high-pressure H
2". Physical Review Letters. 107 (2): 025501. Bibcode:2011PhRvL.107b5501M. doi:10.1103/PhysRevLett.107.025501. PMID 21797616 . Retrieved 19 November 2016. - 1 2 洪广言 (2014). "3.2.4 稀土氢化物" [Rare earth hydrides]. 稀土化学导论[Introduction to Rare Earth Chemistry]. 现代化学基础丛书 (in Chinese). Vol. 36. 北京: 科学出版社. pp. 57–59. ISBN 978-7-03-040581-4.
- ↑ Bischof, R.; Kaldis, E.; Wachter, P. (February 1983). "EuH2: A new ferromagnetic semiconductor". Journal of Magnetism and Magnetic Materials. 31–34: 255–256. Bibcode:1983JMMM...31..255B. doi:10.1016/0304-8853(83)90239-1.