chembox verifiedrevid 443118556 Name Palladium II fluoride ImageFile PdF2 xtal 1993 unit cell CM 3D ellipsoids.png ImageSize 200px ImageName unit cell of the crystal structure of palladium II fluoride OtherNames Section1 Chembox Identifiers CASNo 13444 96 7 CASNo Ref cascite correct ?? PubChem 83470 EINECS 236 598 8 RTECS Section2 Chembox Properties Pd 1 F 2 Appearance pale violet crystalline solid hygroscopic ref name CRC http www.hbcpnetbase.com CRC Handbook, 89th edition ref Density 5.76 g cm sup 3 sup ref name CRC Solubility reacts with water SolubleOther MeltingPt 952 C ref name CRC Section3 Chembox Structure Coordination octahedral CrystalStruct tetragonal Section4 Chembox Thermochemistry DeltaHf Entropy Section7 Chembox Hazards ExternalMSDS EUClass EUIndex Not listed MainHazards NFPA H NFPA F NFPA R NFPA O RPhrases SPhrases FlashPt PEL Section8 Chembox Related OtherAnions Palladium II chloride br Palladium II bromide br Palladium II iodide OtherCations Nickel II fluoride br Platinum II fluoride br Platinum IV fluoride Palladium II fluoride , also known as palladium difluoride , is the chemical compound of palladium and fluorine with the chemical formula formula PdF sub 2 sub . Synthesis PdF sub 2 sub is prepared by reflux ing palladium II,IV fluoride , Pd sup II sup Pd sup IV sup F sub 6 sub , with selenium tetrafluoride , SeF sub 4 sub . Pd PdF sub 6 sub SeF sub 4 sub 2PdF sub 2 sub SeF sub 6 sub Structure and paramagnetism Like its lighter congener nickel II fluoride , PdF sub 2 sub adopts a rutile type crystal structure , containing octahedral coordination geometry octahedrally coordinated palladium, which has the electronic configuration t sup sub 6 2g e sup sub 2 g . This configuration causes PdF sub 2 sub to be paramagnetic ref name G&E 1153 Greenwood&Earnshaw2nd pages 1152 1153 ref due to two unpaired electrons, one in each e sub g sub symmetry atomic orbital orbital of palladium. See also Palladium fluoride disambiguation Palladium fluo ... more details
Chembox Watchedfields changed verifiedrevid 428904265 ImageFile Sodium chloride 3D ionic.png ImageSize ImageAlt IUPACName europium II sulfide OtherNames Section1 Chembox Identifiers CASNo Ref cascite correct CAS CASNo 12020 65 4 PubChem 82809 SMILES Section2 Chembox Properties Formula EuS MolarMass 184.03 g mol Appearance black powder Density MeltingPt 2250 C BoilingPt Solubility Section3 Chembox Hazards MainHazards FlashPt Autoignition 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 lanthanide s exhibit a typical oxidation state of III. ref name four C. Housecroft. Inorganic Chemistry. 3rd. Essex, England Pearson Education Limited, 2008. Print. ISBN 0 13 175553 6 ref Its Curie temperature T sub c sub is 16.6 K. Below this temperature EuS behaves like a ferromagnetic compound, and above it exhibits simple Paramagnetism paramagnetic properties. ref name two Zhao, F. Sun, H. Su, G. Gao, S. Small, Synthesis and Size Dependant Magnetic Properties of Monodisperse EuS Nanocrystals. 2006 volume 2, No. 2, 244 248. doi 10.1002 smll.200500294 ref 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. ref name five Structure EuS crystallizes in face centered cubic FCC crystal lattice . Both europium and sulfur have octahedral coordination geometry with a coordination number of six. ref name one ref name six Wells A.F. Structural Inorganic Chemistry. 4th. London, England Oxford University Press, 1975. Print. ISBN 0 19 855354 4 ref The Eu S bond lengths are 2.41 . Preparation In the preparation of EuS, powdered europium III oxide Eu sub 2 sub O sub 3 sub is treated with hydrogen sulfide H sub 2 sub S at 1150 C. The crude EuS product is purified by heating at 900 C under vacuum to remove excess sulfur. ref name one Archer, R. D. Mitchel, W. N. Inorganic Syntheses, Europ ... more details
weak effect in most materials, although superconductor s exhibit a strong effect. Paramagnetism main ParamagnetismParamagnetism is a form of magnetism which occurs only in the presence of an externally ... Paramagnetism Permittivity SI electromagnetism units References Reflist External links http ... more details
diamagnetic susceptibility is given a negative sign. Paramagnetism. At least one electron ... calculated with the values from the table. ref Figgis&Lewis, p. 417 ref Paramagnetism Main Paramagnetism ... 2 sup , in a coordination complex provides the simplest illustration of the mechanism of paramagnetism ... is low. Temperature independent paramagnetism Compounds which are expected to be diamagnetic may exhibit this kind of weak paramagnetism. It arises from a second order Zeeman effect in which ..., math overrightarrow L 0 math and the paramagnetism can be attributed to electron spin alone. The total ... includes a contribution from temperature independent paramagnetism. ref Orchard, p. 106 ref Main group ... more details
merge solvated electron date March 2012 discuss talk Electride Merge Image Electride 01.jpg thumb right 200px Cavities and channels in Electride An electride is an ionic chemical compound compound in which an electron is the anion . ref cite journal author Dye, J. L. title Electrons as Anions journal Science journal Science year 2003 volume 301 pages 607 608 doi 10.1126 science.1088103 pmid 12893933 issue 5633 ref Solutions of alkali metal s in ammonia are electride salts. ref Holleman, A. F. Wiberg, E. Inorganic Chemistry Academic Press San Diego, 2001. ISBN 0 12 352651 5 ref In the case of sodium, these blue solutions consist of Na NH sub 3 sub sub 6 sub sup sup and solvated electron s Na 6 NH sub 3 sub Na NH sub 3 sub sub 6 sub sup sup ,e sup sup The cation Na NH sub 3 sub sub 6 sub sup sup is an octahedral molecular geometry octahedral coordination complex . Solid salts Addition of 2.2.2 Cryptand 2,2,2 cryptand to a solution of Na NH sub 3 sub sub 6 sub sup sup e sup sup affords Na 2,2,2 crypt sup sup e sup sup . Evaporation of these solutions yields a blue black paramagnetic salt with the formula Na 2,2,2 crypt sup sup e sup sup . The solid salts decompose above 240 K, although Ca sub 24 sub Al sub 28 sub O sub 68 sub sup 4 sup e sup sup sub 4 sub is stable at room temperature. ref cite journal author Buchammagari, H. et al. year 2007 title Room Temperature Stable Electride as a Synthetic Organic Reagent Application to Pinacol Coupling Reaction in Aqueous Media journal Org. Lett. publisher ACS Publications volume 9 issue 21 pages 4287 4289 url http pubs.acs.org doi abs 10.1021 ol701885p doi 10.1021 ol701885p pmid 17854199 pmc ref In these salts, the electron is delocalized between the cation s. Electrides are paramagnetism paramagnetic and Mott insulator s. Reactions Solutions of electride salts are powerful reducing agent s, as demonstrated by their use in the Birch reduction . Evaporation of these blue solutions affords a mirror of Na. Such solutions slo ... more details
Image Shubnikv.JPG right 250px thumb Lev Shubnikov Lev Vasilyevich Shubnikov lang ru lang uk September 9, 1901&mdash November 10, 1937 was a USSR Soviet experimental physicist who worked in the Netherlands and USSR . Shubnikov was born into the family of a Saint Petersburg accountant. After graduating from a Gymnasium school gymnasium he entered Saint Petersburg State University Leningrad University . This was the first year of the Russian Civil War and he was the only student of that year attending the physics department. While yachting in the Gulf of Finland in 1921, he accidentally sailed from Saint Petersburg to Finland , was sent to Germany and could not return to Russia until 1922. He then continued his education in the Leningrad Polytechnical Institute , graduating in 1926. During his university training he worked with Ivan Obreimov , developing a new method for growing monocrystal s of metals. In 1926, at the recommendation of Abram Ioffe , he was sent to the Leiden cryogenic laboratory of Wander Johannes de Haas in the Netherlands he worked there until 1930. Shubnikov studied bismuth crystals with low impurity concentrations, and in cooperation with Wander Johannes de Haas he discovered magnetoresistance oscillations at low temperatures in magnetic field s the Shubnikov De Haas effect . The importance of this effect for condensed state physics became completely clear only much later. Today this effect is one of the principal instruments used in studying the quantum electron properties of solids. In 1930 Shubnikov returned to Kharkov and established there the first Soviet cryogenic laboratory. He also discovered the antiferromagnetism in 1935 and paramagnetism in 1936, together with Boris Lazarev of solid state hydrogen . He was one of the first to study liquid helium . In 1937, at the height of the Great Purge , the NKVD launched the UPTI Affair Ukrainian Physics and Technology Institute Affair on the basis ... more details
In chemistry a Zintl phase is the product of a reaction between group 1 alkali metal s or group 2 alkaline earth s and post transition metal s or metalloid s from group 13, 14, 15 or 16. Zintl phases were named for the German chemist Eduard Zintl who investigated them in the 1930s. ref name Kauzlarich S.M. Kauzlarich, Encyclopedia of Inorganic chemistry, 1994, John Wiley & Sons, ISBN 0 471 93620 0 ref The term Zintl Phases was first used by Fritz Laves Laves in 1941. ref name Kauzlarich Zintl phases are a subgroup of brittle , high melting point intermetallic compounds which are diamagnetism diamagnetic or exhibit temperature independent paramagnetism , are poor Electrical conduction conductors or semiconductor s. ref name Sevov Sevov, S.C., Zintl Phases in Intermetallic Compounds, Principles and Practice Progress, Westbrook, J.H. Freisher, R.L. Eds. John Wiley & Sons. Ltd., Chichester, England, 2002, pp. 113 132 ref Zintl noted that there was an atomic volume contraction when these compounds were formed and realised this could indicate cation formation. ref name Sevov He suggested that the structures of Zintl phases were ionic, where there was complete electron transfer from the more electropositive metal. ref name Sevov The structure of the ion anion nowadays called the Zintl ion should then be considered on the basis of the resulting electronic state. These ideas were further developed to become the Zintl rule or Zintl Klemm concept , where the polyanion structure should be similar to an isoelectronic element. ref name Kauzlarich Examples of Zintl phases NaTl, where it is now known that the structure consists of a polymeric anion Tl sup nowiki &minus nowiki sup sub n sub with a covalent diamond structure with Na sup sup ions fitted into the anionic lattice. ref name Kauzlarich NaSi where the polyanion is tetrahedron tetrahedral Si sub 4 sub sup 4 nowiki &minus nowiki sup similar to phosphorus molecule P sub 4 sub . ref name Kauzlarich Na sub 2 sub Tl which the po ... more details
chembox verifiedrevid 430379155 Name EuFOD ImageFile Eufod.png OtherNames Eu fod sub 3 sub Section1 Chembox Identifiers CASNo 17631 68 4 Section2 Chembox Properties Formula C sub 30 sub H sub 30 sub EuF sub 21 sub O sub 6 sub MolarMass 1037.49 g mol Appearance Yellow powder Density Solubility MeltingPt 203 207 C BoilingPt EuFOD is the chemical compound with the formula Eu OCC CH sub 3 sub sub 3 sub CHCOC sub 3 sub F sub 7 sub sub 3 sub , also called Eu fod sub 3 sub . This coordination compound is used primarily as a shift reagent in NMR spectroscopy . It is the premier member of the lanthanide shift reagents and was popular in the 1970s and 1980s. Structure and reactivity Eu fod sub 3 sub consists of three bidentate acac acetylacetonato ligands bound to a Europium Eu III center. This metal atom has an electron configuration of f sup 6 sup . The six electrons are unpaired each in a different singly occupied f orbital which makes the molecule highly paramagnetic . The complex is a Lewis acid , being capable of expanding its coordination number of six to eight. The complex displays a particular affinity for HSAB theory hard Lewis bases, such as the oxygen atom in ether s and the nitrogen of amine s. It is soluble in nonpolar solvents, even more so than related complexes of acetylacetone and hexafluoroacetylacetone . The fod ligand is a derivative of heptafluorobutyric acid . Uses As an NMR shift reagent The original application of Eu fod sub 3 sub was for analyzing diastereomeric compounds in NMR spectroscopy. The paramagnetic compound induces additional chemical shift in the protons near any Lewis basic site to which it binds in a molecule. This change helps resolve closely spaced signals by separating the ones from these hydrogens away from others that are not near basic sites but whose normal chemical shift is similar. Only small amounts of shift reagents are used, because otherwise the paramagnetism of the reagent shortens the spin lattice relaxation times of the ... more details
Wikify date March 2011 Refimprove date March 2011 Heavy fermion superconductors are a type of unconventional superconductors Unconventional superconductor . The first heavy fermion superconductor, CeCu sub 2 sub Si sub 2 sub , was discovered by Frank Steglich in 1978. ref cite journal doi 10.1103 PhysRevLett.43.1892 title Superconductivity in the Presence of Strong Pauli Paramagnetism CeCu sub 2 sub Si sub 2 sub year 1979 last1 Steglich first1 F. first2 H. journal Physical Review Letters volume 43 pages 1892 last2 Aarts last3 Bredl first3 C. last4 Lieke first4 W. last5 Meschede first5 D. last6 Franz first6 W. last7 Sch fer first7 H. bibcode 1979PhRvL..43.1892S ref Since then over 30 heavy fermion superconductors were found in materials based on Ce, U , with a critical temperature up to 2.3 K in CeCoIn sub 5 sub . ref cite journal doi 10.1088 0953 8984 13 17 103 title Heavy fermion superconductivity in CeCoIn sub 5 sub at 2.3 K year 2001 last1 Petrovic first1 C. last2 Pagliuso first2 P.G. last3 Hundley first3 M.F. last4 Movshovich first4 R. last5 Sarrao first5 J.L. last6 Thompson first6 J.D. last7 Fisk first7 Z. last7 Monthoux first7 P. journal Journal of Physics Condensed Matter volume 13 pages L337 ref class wikitable Material T sub C sub K CeCu sub 2 sub Si sub 2 sub 0.7 CeCoIn sub 5 sub 2.3 CeIn sub 3 sub 0.2 UPt sub 3 sub 0.48 URu sub 2 sub Si sub 2 sub 1.3 UPd sub 2 sub Al sub 3 sub 2.0 UPd sub 2 sub Al sub 3 sub 1.1 Heavy Fermions are intermetallic compounds, containing rare earth or actinide elements. The f electrons of these atoms hybridize with the normal conduction electrons leading to quasiparticles with an enhanced mass. citation needed date March 2011 From specific heat measurements C C T sub C sub one knows that the Cooper pair s in the superconducting state are also formed by the heavy quasiparticles. ref Neil W. Ashcroft and N. David Mermin, Solid State Physics ref In contrast to normal superconductors it cannot be described by BCS Theory. Due to th ... more details
response is diamagnetism is called a diamagnet. ParamagnetismParamagnetism is a weak positive response to a magnetic field due to rotation of electron spin physics spins . Paramagnetism occurs in certain ... more details
s and Van Vleck paramagnetism ref nofollow http www.answers.com topic van vleck paramagnetism Van Vleck paramagnetism , Answers.com ref are also named after him. Dr. Van Vleck died in Cambridge ... more details
In chemistry a boride is a chemical compound between boron and a less electronegativity electronegative element, for example silicon boride SiB sub 3 sub and SiB sub 6 sub . The borides are a very large group of compounds that are generally high melting and are not ionic in nature. Some borides exhibit very useful physical properties. The term boride is also loosely applied to compounds such as B sub 12 sub As sub 2 sub N.B. Arsenic has an electronegativity higher than boron that is often referred to as boron arsenide icosahedral boride . Ranges of compounds The borides can be classified loosely as boron rich or metal rich, for example the compound Yttrium borides YB sub 66 sub at one extreme through to Nd sub 2 sub Fe sub 14 sub B at the other. The generally accepted definition is that if the ratio of boron atoms to metal atoms is 4 1 or more the compound is boron rich, if it is less, then it is metal rich. Boron rich borides B M 4 1 or more The main group metals, lanthanide s and actinide s form a wide variety of boron rich borides, with metal boron ratios up to Yttrium borides YB sub 66 sub . The properties of this group vary from one compound to the next, and includes examples of compounds that are semi conductors, superconductors, diamagnetism diamagnetic , paramagnetism paramagnetic , ferromagnetism ferromagnetic or antiferromagnetism anti ferromagnetic . ref cite journal author Lundstrom T journal Pure & Applied Chem year 1985 volume 57 issue 10 page 1383 title Structure, defects and properties of some refractory borides format free download pdf doi 10.1351 pac198557101383 ref They are mostly stable and refractory. Some metallic dodecaborides contain boron icosahedra, others for example yttrium , zirconium and uranium have the boron atoms arranged in cuboctahedron cuboctahedra . ref cite journal last Matkovich first V.I. coauthors J Economy, R F Giese Jr, R Barrett year 1965 title The structure of metallic dodecaborides journal Acta Cryst. volume 19 pages 105 ... more details
chembox verifiedrevid 449207593 ImageFile ReCl3structure.jpg ImageName Rhenium Trichloride Crystal Structure IUPACName Rhenium III chloride OtherNames Rhenium trichloride Section1 Chembox Identifiers CASNo 13569 63 6 EINECS 236 987 1 PubChem 83581 InChI 1S 3ClH.Re h3 1H q 3 p 3 SMILES Cl Re Cl Cl Section2 Chembox Properties Formula ReCl sub 3 sub MolarMass 292.57 g mol Appearance red, crystalline, nonvolatile solid Density 4800 kg m Solubility hydrolyzes to form Re sub 2 sub O sub 3 sub sup . sup xH sub 2 sub O. MeltingPt N A BoilingPt 500 C decomposes Section3 Chembox Structure MolShape trimer chemistry trimeric solid and in solution br Dimer chemistry dimeric in acetic acid CrystalStruct Rhombohedral , Pearson symbol hR72 SpaceGroup R 3m, No. 166 Dipole Section7 Chembox Hazards ExternalMSDS External MSDS http asp.cerac.com CatalogNet default.aspx?p msdsFile&msds m001119.htm MainHazards Corrosive C Section8 Chembox Other OtherAnions Rhenium tribromide br Rhenium triiodide OtherCpds Rhenium trichloride ReCl sub 3 sub is a chemical compound compound of rhenium and chlorine . It was first discovered in 1932 by Geilnann, Wriuce, and Biltz. ref Geilnann, W. Wriuce, F. W. Wilhelm Biltz Biltz. W. Nachr. Ges. Wiss. Gottingen 1932, 579. ref Structure and physical properties The crystal structure of rhenium trichloride consists of well defined Re sub 3 sub Cl sub 9 sub units that are connected by chlorine atom bridges. The Re sub 3 sub Cl sub 9 sub unit structure also applies to rhenium trichloride dissolved in a variety of solvents, with the only possible exception being the dimer structure when dissolved in acetic acid. The Re sub 3 sub Cl sub 9 sub crystal structure has C sub 3v sub symmetry. ref name Colton Rhenium trichloride is comparatively non volatile but produces a green vapour during strong heating. It may have a very small temperature independent paramagnetism , but the susceptibility is ambiguous. ref name Colton Colton, R. Chemistry of rhenium and technetium. L ... more details
Phosphorus 31 NMR spectroscopy NMR stands for nuclear magnetic resonance is an analytical technique. Solution sup 31 sup P NMR is one of the more routine NMR techniques because sup 31 sup P has an isotopic abundance of 100 and a relatively high magnetogyric ratio . The sup 31 sup P nucleus also has a spin of , making spectra relatively easy to interpret. Phosphorus is commonly found in organic compound s and coordination complexes as phosphines , making it useful to measure sup 31 sup P NMR spectra routinely. Operational aspects With a magnetogyric ratio 42.5 of that for sup 1 sup H, sup 31 sup P NMR signals are observed near 212 MHz on a 11.7 Tesla magnet used for 500 MHz sup 1 sup H NMR measuements . Chemical shifts are referenced to 85 phosphoric acid , which is assigned the chemical shift of 0, with positive shifts to low field high frequency. ref name hoffman Due to the inconsistent nuclear Overhauser effect , integrations are not useful. ref name hoffman cite web publisher Hebrew University author Roy Hoffman year 2007 title sup 31 sup Phosphorus NMR url http chem.ch.huji.ac.il nmr techniques 1d row3 p.html ref Most often, spectra are recorded with protons decoupled. Applications in chemistry sup 31 sup P NMR spectroscopy is useful to assay purity and to assign structures of phosphorus containing compounds because these signals are well resolved and often occur at characteristic frequencies. Chemical shifts and coupling constants span a large range but sometimes are not readily predictable. Chemical shifts The ordinary range of chemical shifts ranges from abut 250 to 250, which is much wider than typical for sup 1 sup H NMR. Unlike 1H NMR spectroscopy, 31P NMR shifts are primarily not determined by the magnitude of the diamagnetic shielding, but are dominated by the so called paramagnetic shielding tensor unrelated to paramagnetism . The paramagnetic shielding tensor, sub p sub , includes terms that describe the radial expansion related to charge , energie ... more details
by future workers in that area. Pierre Curie studied ferromagnetism , paramagnetism , and diamagnetism for his doctoral thesis, and discovered the effect of temperature on paramagnetism which is now ... more details
The Bohr van Leeuwen theorem is a theorem in the field of statistical mechanics . The theorem shows that when statistical mechanics and classical mechanics are applied consistently, the thermal average of the magnetization is always zero. ref John Hasbrouck van Vleck stated the Bohr van Leeuwen theorem as At any finite temperature, and in all finite applied electrical or magnetical fields, the net magnetization of a collection of electrons in thermal equilibrium vanishes identically. van Vleck, 1932 ref This makes magnetism in solids solely a quantum mechanical effect and means that classical physics cannot account for diamagnetism , paramagnetism or ferromagnetism . ref name Aharoni harvnb Aharoni 1996 ref History What is today known as the Bohr van Leeuwen theorem was discovered by Niels Bohr in 1911 in his doctoral dissertation ref harvnb Bohr 1972 ref and was later rediscovered by Hendrika Johanna van Leeuwen in her doctoral thesis in 1919. ref harvnb van Leeuwen 1921 ref In 1932, John Hasbrouck van Vleck van Vleck formalized and expanded upon Bohr s initial theorem in a book he wrote on electric and magnetic susceptibilities. ref name vanVleck harvnb van Vleck 1932 ref The significance of this discovery is that classical physics does not allow for such things as paramagnetism , diamagnetism and ferromagnetism and thus quantum physics and Theory of relativity relativity are needed to explain the magnetic events. ref name Aharoni This result, perhaps the most deflationary publication of all time, ref harvnb van Vleck 1992 ref may have contributed to Bohr s development of a quasi classical Bohr model theory of the hydrogen atom in 1913. Proof An intuitive proof The Bohr van Leeuwen theorem applies to an isolated system that cannot rotate an isolated star could start rotating if exposed to a field . ref name Feynman harvnb Feynman Leighton Sands 2006 ref If, in addition, there is only one state of thermal equilibrium in a given temperature and field, and the system ... more details
be no diamagnetism , paramagnetism or ferromagnetism. The property of ferromagnetism is due ... paramagnetism. Ferromagnetism involves an additional phenomenon, however the dipoles tend to align ... more details
caused by the unpaired electrons. Paramagnetism main Paramagnetism In a paramagnetic material there are unpaired ... functions . Thus, now the spins would be parallel ferromagnetism in a solid, paramagnetism in two ... more details
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