- The first reduced rare earth halide with a group 11 element as interstitial: La3I3Au
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The title compound was synthesized from La, LaI3 and Au under Ar atmosphere in the temperature range 850-950°C. It crystallizes in the cubic space group I4132 with lattice constant a = 12.661(2) A. The structure features Au-centered helical octahedron chains arranged in all three directions with 90 degree turns. It is the first reduced rare earth halide with a group 11 interstitial. It is very air and moisture sensitive, and produces crimson-colored Au precipitate similar to Gold Purple of Cassius upon reaction with water or ethanol.
- Mattausch, Hansjuergen,Zheng, Chong,Kienle, Lorenz,Simon, Arndt
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- Rare earth halides Ln4X5Z. Part 1: C and/or C 2 in Ln4X5Z
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The compounds Ln4X5Cn (Ln = La, Ce, Pr; X = Br, I and 1.0 3, Ln metal and graphite in sealed Ta-ampoules at temperatures 850 °C 4I5C1.5: a = 19.849(4) A, b = 4.1410(8) A, c = 8.956(2) A, β = 103.86(3)°, La 4I5C2.0: a = 19.907(4) A, b = 4.1482(8) A, c = 8.963(2) A, β = 104.36(3)°, Ce4 Br 5C1.0: a = 18.306(5) A, b = 3.9735(6) A, c = 8.378(2) A, β=104.91(2)°, Ce4Br5C 1.5: a = 18.996(2) A, b = 3.9310(3)A, c = 8.282(7) A, β = 106.74(1)°, Pr4 Br5C1.3: a = 18.467(2) A, b = 3.911(1) A, c = 8.258(7) A, β = 105.25(1)° and Pr4Br5C1.5: a = 19.044(2) A, b = 3.9368(1) A, c = 8.254(7) A, β = 106.48(1)°. In the crystal structure the lanthanide metals are connected to Ln 6-octahedra centered by carbon atoms or C2-groups. The Ln6-octahedra are condensed via opposite edges to chains and surrounded by X atoms which interconnect the chains. A part n of isolated C-atoms is substituted by 1-n C2-groups. The C-C distances range between 1.26 and 1.40 A. In the ionic formulation (Ln3+) 4(X-)5(C4-)n(C 2 m-)1-n · e- with 0 22-, C24- C26-), there are 1 - 5 electrons centered in metal-metal bonds.
- Mattausch, Hansjuergen,Schaloske, Manuel C.,Hoch, Constantin,Zheng, Chong,Simon, Arndt
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- Rare-earth iodides in ionic liquids: Crystal structures of [bmpyr]4[LnI6][Tf2N] (Ln = La, Er)
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Deliberately designed ionic liquids can be excellent solvents for organic reactions with lanthanide compounds, e.g. Lewis catalysis with trivalent lanthanides. Little is known about the solvation and complexation of these Lewis-acid catalysts in these-still uncommon-solvents, although the knowledge of these processes is a prerequisite for a basic understanding of reaction mechanisms and catalytic cycles. Therefore, we have investigated the chemical behaviour of rare-earth metal iodides in the ionic liquid [bmpyr][Tf2N] (bmpyr = 1,1-n-butyl-methylpyrrolidinium; Tf2N = bis(trifluoromethanesulfonyl)-amide). Compounds of the general composition [bmpyr]4[LnI6][Tf2N] could be crystallized from solutions of LnI3 (Ln = La, Er), in [bmpyr][Tf2N]. Single-crystal X-ray diffraction data show that the trivalent rare-earth cations are octahedrally coordinated by six iodide anions. Eight cations of the ionic liquid are located tangentially above each of the triangular faces of the [LnI6] octahedron. According to the size of the trivalent cation, the crystal structure adjusts itself by tilting of the [LnI6] octahedra to accommodate one anion of the ionic liquid, bis(trifluoromethanesulfonyl)-amide, which completes the crystal structure of the composition [bmpyr]4[LnI6][Tf2N].
- Babai, Arash,Mudring, Anja-Verena
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- La2Tel2: A new layered telluride iodide with unusual electrical properties
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A new layered metal-rich telluride halide, La2Tel2, has been synthesized by heating stoichiometric mixtures of Lal3, La, and Te under argon at 900°C, and its structure has been refined from X-ray powder diffraction data. The compound crystallizes in the 3R-Lu 2CCl2 structure type (rhombohedral space group R3m with a = 4.5074(4) A, c = 32.528(2) A, and Z = 3). The crystal structure is composed of infinite layers of edge-sharing, Te-centered metal atom octahedra and iodine atoms separating these layers to form three close-packed I-Ln-Te-Ln-I slabs within the unit cell. The title compound is metallic at room temperature and exhibits an anomaly in the resistivity around 140 K which is closely related to changes in the a lattice parameter with temperature. The chemical bonding and metallic properties of La2Tel2 can be plausibly understood in terms of an ionic description (Ln3+)2Te 2-(I-)2(e)2 where two electrons are delocalized in the La 5d conduction band.
- Ryazanov, Mikhail,Simon, Arndt,Mattausch, Hansjurgen
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- LiLa6I12Os, a substitutional derivative of rhombohedral La(La6I12Os)
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The series of quaternary rare-earth-metal halide cluster compounds ALa 6I12Z with transition metal interstitials Z and alkali or alkaline-earth metal cations A has been expanded to include A=Li. The compounds synthesized by high-temperature solid-state techniques for Z=Os, Ir, Pt, Ru are isotypic with rhombohedral R7X12Z (R3, Z=3). The refined single X-ray crystal structure of (Li0.967La 0.033)La6I12Os is reported, along with supportive results from a Rietveld analysis of neutron powder diffraction from a different sample, 7Li MAS-NMR, and electronic resistivity and magnetic susceptibility measurements. The samples show continuous Li 1-xLax cation compositions and are generally semiconductors, but their complex paramagnetic properties are not those of simple spin-only systems.
- Jensen, Elizabeth A.,Corbett, John D.
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- The structural change of lanthanum diiodide upon hydrogenation
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Slowly heating LaI2 under 1atm hydrogen to 650°C leads to LaI2H, analyzed as LaI2H0.95(3), accompanied by a structural change from tetragonal to hexagonal. Sharp reflections in the XRD pattern can be indexed in P63/mmc with a=4.2158(7)A? and c=15.508(3)A?, however, diffuse reflections indicate a polytypic intergrowth of MoS2 and NbS2 type structures. The earlier determined miscibility gap between LaI2 and LaI2H x (x≈0.5) is closely related to the change of the structure. The Pauli paramagnetism for LaI2, χP = 43(2)×10 -6cm3/mol, derived from measurements on LaI2 and LaI2H is in good agreement with the value estimated from band structure calculations.
- Ryazanov,Simon,Mattausch,Kremer
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- The aluminide iodides La24Al12I21 and La10Al5I8: Compounds with intermetallic La-A1 fractions and La-Al clusters
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Reacting pieces of La, LaI3 and A1 filings (molar ratio 22: 8: 15) at 800 °C-825 °C results in La24Al12I 21 (70% yield) together with La10Al5I 8 (10 % yield), besides known La3Al2I 2 and La2Al2I. Both new compounds form golden coloured needles. La10Al5I8 is brittle, whereas La24Al12I21 is shaped as hair-like easily deformable bundles. Both are monoclinic, space group C2/m, La 24Al12I21 with a = 35.753(7) A, b = 4.327(1) A, c = 27.442(6) A, β = 116.62(3)° and La 10Al5I8 with a = 19.649(1) A, b = 4.296(1) A, c = 18.0290(1) A and β = 96.67(3)°. The La atoms form trigonal prisms condensed into double chains along [010]. The La prisms are centered by A1 atoms which form Al6 rings connected into chains. The La-Al strands are surrounded by I atoms in La24Al 12I21, whereas in La10Al5I 8 they are connected to form corrugated sheets separated by close packed layers of I atoms together with Al atoms. The octahedral voids around the Al atoms are occupied by La atoms, and such La6Al clusters are connected via opposite edges to octahedra chains along [010].
- Mattausch, Hansjuergen,Oeckler, Oliver,Hoch, Constantin,Simon, Arndt
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- Investigations on iodomercurates: Crystal structures of bis[di(12-crown-4)lithium]octaiodotrimercurate(II) and catena-poly{di[(benzo-15-crown-5)potassium]pentaiododimercurate(II)} with new iodomercurate anions and a lanthanum(III) tetraidomercurate(II), [La6(OH)8(O)(H2O)24][HgI 4]4 with a hexanuclear complex cation
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By diffusion of methanolic solutions of LiI/HgI2 and 12-crown-4, resp. crystals of [Li(12-crown-4)2]2[Hg3I8] (1) were obtained. They contain a new finite octaiodotrimercurate(II) ion which, contrary to the twisted [Hg3I8]2- ion known so far, is built up linearity from three [HgI4] tetrahedra sharing common edges. From solutions of KI, HgI2, and benzo-15-crown-5, a complex of formal composition [K(benzo-15-crown-5)2][Hg2I5] (2) was formed containing a polymeric iodomercurate ion with a chain structure built up from [Hg2I6] units trans connected by common iodide ions. On both sides of the chains [K(benzo-15-crown-5)2]+ cations are bounded by CH...I interactions. From an aqueous solution of LaI3/HgI2 the hexanuclear complex [La6(H2O)24-(OH)8(O)][(HgI 4)4] (3) was obtained. The six La(III) ions form an octahedron with an O ion in the center, eight three dentate OH ions situated above the faces of the octahedron bind to the three La ions forming the face. Each La ion is further bound to four coordination water molecules. Cations and anions are connected via H bonds.
- Pickardt,Wiese,Von Chrzanowski,Borowski
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- Substitution experiments on superconducting La2C2X2 (X = Cl, Br, I)
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The layered carbide bromide La2C2Br2 becomes superconducting at 6.2 K. We studied the matrix effect on Tc due to (isoelectronic) halogen substitution. Tc increases with the amount of substitution by chlorine to a maximum value of 7.2 K, and it decreases when Br- is partially substituted by I-. La2C2I2 itself is non-superconducting down to 2 K. However, substitution of I- by 10% Cl- leads to superconductivity at 2.2 K.
- Ahn,Mattausch,Simon
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- Some phosphide halides of lanthanum and related compounds
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The pnictide halides La2I2P, La2I 2As, La2I2Sb, La2Br2P and Y2Br2P have been synthesized from lanthanum and yttrium, red phosphorus, arsenic, and
- Oeckler, Oliver,Mattausch, Hansjürgen,Simon, Arndt
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- The lanthanumiodideethanide o-La5I9(C2) - The orthorhombic high temperature modification
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o-La5I9(C2) is synthesized by reaction of LaI3, La metal and graphite powder in sealed Ta containers at 850°C a = 8.0247(16) A, b = 16.887(3) A, c = 35.886(7) A. o-Ce5I9(C2) is isotypic with the lattice parameters a = 7.9284(4) A, b = 16.714(1) A, c = 35.530(3) A. o-La5I9(C2) transforms at 800°C to the triclinic low temperature modification t-La5I9(C 2). The transformation is reversible. The La atoms form trigonal bipyramids centered by C2 groups. These units are connected by iodine atoms above the faces (f), edges (e) and corners according to La 5(C2)I(f)iI(e)i-i 2/2I(e)i-a7/2I(e)a-i 7/2. The C-C distance in the C2 unit is 1.45(2) A. The crystals with greenish luster are moisture sensitive.
- Mattausch, Hansjuergen,Hoch, Constantin,Simon, Arndt
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- Structural characterization of methanol substituted lanthanum halides
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The first study into the alcohol solvation of lanthanum halide [LaX3] derivatives as a means to lower the processing temperature for the production of the LaBr3 scintillators was undertaken using methanol (MeOH). Initially the de-hydration of {[La(μ-Br)(H2O)7](Br)2}2 (1) was investigated through the simple room temperature dissolution of 1 in MeOH. The mixed solvate monomeric [La(H2O)7(MeOH)2](Br)3 (2) compound was isolated where the La metal center retains its original 9-coordination through the binding of two additional MeOH solvents but necessitates the transfer of the innersphere Br to the outersphere. In an attempt to in situ dry the reaction mixture of 1 in MeOH over CaH2, crystals of [Ca(MeOH)6](Br)2 (3) were isolated. Compound 1 dissolved in MeOH at reflux temperatures led to the isolation of an unusual arrangement identified as the salt derivative {[LaBr2.75·5.25(MeOH)]+0.25 [LaBr3.25·4.75(MeOH)]-0.25} (4). The fully substituted species was ultimately isolated through the dissolution of dried LaBr3 in MeOH forming the 8-coordinated [LaBr3(MeOH)5] (5) complex. It was determined that the concentration of the crystallization solution directed the structure isolated (4 concentrated; 5 dilute) The other LaX3 derivatives were isolated as [(MeOH)4(Cl)2La(μ-Cl)]2 (6) and [La(MeOH)9](I)3·MeOH (7). Beryllium Dome XRD analysis indicated that the bulk material for 5 appear to have multiple solvated species, 6 is consistent with the single crystal, and 7 was too broad to elucidate structural aspects. Multinuclear NMR (139La) indicated that these compounds do not retain their structure in MeOD. TGA/DTA data revealed that the de-solvation temperatures of the MeOH derivatives 4-6 were slightly higher in comparison to their hydrated counterparts.
- Boyle, Timothy J.,Ottley, Leigh Anna M.,Alam, Todd M.,Rodriguez, Mark A.,Yang, Pin,Mcintyre, Sarah K.
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p. 1784 - 1795
(2010/07/03)
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- Lanthanide(III) halides: Thermodynamic properties and their correlation with crystal structure
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Temperatures and enthalpies of phase transitions of 17 lanthanide(III) halides determined experimentally are reported. Correlations were made between temperature of fusion of lanthanide(III) halides, on the one hand, and enthalpy of fusion, on the other, versus atomic number of lanthanide. According to this classification, the lanthanide(III) halides split into groups, as also do the corresponding crystal structures. A correlation between the crystal structure of lanthanide(III) halides and their respective entropy of fusion (or entropy of fusion + entropy of solid-solid phase transition) was inferred from the aforementioned features. Fusion in those halides with hexagonal, UCl3-type and orthorhombic, PuBr3-type, structures entails an entropy of fusion change (or entropy of fusion + entropy of solid-solid phase transition change) by 50 ± 4 J mol-1 K-1. The homologous entropy change within the group of halides having the rhomboedric, FeCl3-type, structure, is smaller and equals 40 ± 4 J mol-1 K-1. Halides with monoclinic, AlCl3-type, crystal structure constitute a third group associated to an even smaller entropy change upon fusion, only 31 ± 4 J mol-1 K-1. The halides with lower entropies of fusion also have a lower S1300 K - S298 K indicating either a higher degree of order in the liquid or a higher entropy in the solid at room temperatures.
- Rycerz,Gaune-Escard
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p. 167 - 174
(2008/10/09)
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- Gd7I12Zn: A group 12 atom in the octahedral Gd 6 cluster
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The title compound was synthesized from Gd, GdI3 and Zn under Ar atmosphere at 850°C. It crystallizes in the space group R3 (No. 148) with lattice constants a = 15.686(1) A and c = 10.4882(8) A. The structure features isolated Zn-centered Gd6 octahedra with all edges and corners capped by I atoms. The disorder of the Gd atoms is rationalized via electron microscopic techniques. A computational analysis using the extended Hueckel method has been carried out in order to understand the bonding of this compound. The structure of isotypic La7I12Co is also remarked (a = 16.040(1) A and c = 10.905(2) A).
- Lukachuk, Mar'yana,Kienle, Lorenz,Zheng, Chong,Mattausch, Hansjuergen,Simon, Arndt
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p. 4656 - 4660
(2009/02/03)
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- Isolated and edge-sharing interstitially stabilized metal tetrahedra {M4Z} in La4ZBr7, M9Z 4I16, and BaM4Z2I8 (M = La,Ce). The nature of Z
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Metallothermic reductions of LaBr3, LaI3 and CeI 3 with barium metal resulted in single crystals of La 4ZBr7, M9Z4I16 and BaM4Z2I8 (M = La,Ce) as by-products, subject to apparently ubiquitous oxygen and/or nitrogen (= Z) impurities. The crystal structure of La4ZBr7 (1, orthorhombic, Pnma, Z = 4, a = 1212.4(1), b = 1404.8(2), c = 804.7(1) pm, R 1 = 0.0358 for I>2σI with N:O = 0.91:0.09) is determined by isolated {La4Z} tetrahedra surrounded by and connected through bromide ligands. In the crystal structure of Ce9Z4I 16 (2, orthorhombic, Fddd, Z = 8, a = 890.0(1), b = 2264.1(2), c = 4279.5(4) pm, R1 = 0.0262 for I>2σI with N:O = 0.75:0.25), {Ce4Z} tetrahedra are connected to {Ce4/2Z} chains via common edges and further to layers by iodide ligands. The layers are stacked and connected via the ninth cerium atom according to Ce[{Ce4/2Z}I 4]4. Similar {La4/2Z} chains and BaI 8/4 chains run perpendicularly to each other and are connected via common iodide ions in the crystal structure of BaLa4Z 2I8 = Ba2[{La4/2Z}I 4]4 (3, monoclinic, C2/c, Z = 4, a = 897.5(1), b = 2162.4(3), c = 1229.3(2), β = 110.32(1)°, R1 = 0.0261 for I>2σI with N:O = 0.54:0.46). The nature of the interstitial Z, oxygen and/or nitrogen, is evaluated.
- Gerlitzki, Niels,Hammerich, Stefanie,Pantenburg, Ingo,Meyer, Gerd
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p. 2024 - 2030
(2008/10/09)
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- Reduced lanthanum halides with Ge as interstitials: La2I 2Ge, La2I2Ge2, La3Cl 2Ge3, La3Br2Ge3, La 3I3Ge, La
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The title compounds were synthesized from La, LaX3 (X = Cl, Br and I) and Ge under Ar atmosphere at temperatures 860-1200°C. Their structures are characterized by Ge-centered La6 octahedra or trigonal prisms. Ge atoms form planar zig
- Mattausch, Hansjuergen,Zheng, Chong,Ryazanov, Mikhail,Simon, Arndt
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p. 302 - 308
(2008/10/09)
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- On the reactivity of lanthanide iodides LnIx (x < 3) formed in the reactions of lanthanide metals with iodine
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The reduced lanthanide iodides of the composition LnIx (Ln = Sc, Y, La, Ce, Pr, Gd, Ho, and Er; x 3) were obtained by the reaction of an excess of the appropriate metal with iodine at high temperatures. The diamagnetism of the Sc, Y, and La d
- Khoroshenkov,Petrovskaya,Fedushkin,Bochkarev
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p. 699 - 702
(2008/10/08)
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- La3X3Z - Compounds with Condensed La6Z Octahedra Helically Connected in Three Dimensions
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The subhalides La3X3Z (X=Br, I, Z=Si, P, As, Sb, C2) were synthesized from stoichiometric mixtures of La, LaX3 and Z under Ar atmosphere in sealed Ta ampoules at 950°C to 1200°C for 3-30 days. La3X3Z (X=Br, I, Z=Si, P, As, Sb) is isostructural to Gd3Cl3C (Z=8, space group I4132, No. 214) which can be described as a defect NaCl type. This structure is characterized by the main group element Z centered octahedra propagating helically in three dimensions. The lattice constants a are 12.163(3), 12.4267(5), 12.533(1) and 12.780(1) ? for La3Br3Si, La3I3P, La3I3As and La3I3Sb, respectively. The excess electrons in the La dxy conduction band lead to a metallic behavior for these compounds. La3Br3Si undergoes a metal-insulator transition at 36 K which is attributed to a structural change. La3Br3C2 crystallizes in a different space group C2221 (No. 20), Z=16, a=11.5330(6) ?, b=17.0698(6) ?, c=17.0540(8) ?. The C2 units center highly distorted La octahedra. This structure, however, is related to the above I4132 structure in that the edge-sharingLa6 octahedra fill space in a similar way. This compound is a semicondu ctor (electrical gap Eg=0.02 eV) and its conducting property can be understood from the closed-shell electron configuration of (La(3+))3(Br(-))3(C2)(6-).
- Zheng, Chong,Oeckler, Oliver,Mattausch, Hansjuergen,Simon, Arndt
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- Layered lanthanum carbide halide superconductors La2C2(X,X′)2 (X,X′ = Cl, Br, I): Neutron powder diffraction characterization and electronic properties
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The superconducting properties of La2C2(X, X′)2(X, X′ = Cl, Br, I) are investigated. Three different samples of La2C2Br2, which are obtained under different synthesis conditions, show superconductivity at 7.03(5) K. La2C2I2 (Tc≈1.7 K) exhibits slightly different transition temperatures for differently prepared samples. A total of five samples of La2C2(X, X′)2 were investigated by high resolution neutron powder diffraction from room temperature to 1.5 K. Rietveld refinements yield the structural parameters, in particular of the C atoms. These allow us to follow in detail the variation of the interatomic distance in the C2 group. On the basis of the low temperature structural parameters, extended Hueckel band structure calculations were performed and a band of low dispersion along the Γ-N direction in the Brillouin zone was identified. We discuss correlations of structural and electronic properties with the superconducting transition temperatures of the La2C2(X, X′)2 phases.
- Ahn, Kyungsoo,Gibson, Brendan J.,Kremer, Reinhard K.,Mattausch, Hansjuergen,Stolovits, Andres,Simon, Arndt
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p. 5446 - 5453
(2007/10/03)
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- Rare earth iodide complexes of 4-formyl-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one
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Rare earth complexes of 4-formyl-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one (FDPP) having the general formula [Ln(FDPP)4I2]I, where Ln = Y, La, Pr, Nd, Sm, Eu, Gd, Dy, Ho and Er, have been synthesised and characterised by elemental analyses, molar conductance in non-aqueous solvents, electronic, infrared and proton NMR spectra as well as thermogravimetric analyses. FDPP acts as a neutral monodentate ligand coordinating through the ring carbonyl oxygen. Two of the iodide ions are coordinated. A coordination number of six may be assigned to the metal ion in these complexes. The covalency parameters evaluated from the solid state electronic spectra suggest weak covalent character of the metal-ligand bond. The TG data of the lanthanum complex indicate that the complex is stable up to about 140° C and undergoes decomposition in three stages forming lanthanum oxide as the final product.
- Joseph, Siby,Radhakrishnan
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p. 1219 - 1229
(2008/10/09)
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- Planar B4 rhomboids: The rare earth boride halides RE4X5B4
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The new compounds RE4X5B4 (RE = La, Ce, Pr, Gd and X = Br, I) and RE4I5B2C (RE = La, Ce) are prepared via the reaction of RE metal, REX3 and B, or B and C at temperatures 1670 ≥ T ≥ 1270 K in welded tantalum ampoules. Chains of interconnected B4 rhomboids are the characteristic features of the crystal structures. According to band structure calculations, the compounds are one-dimensional metals which undergo a gradual metal-to-semiconductor transition at low temperature as experimentally indicated by the steep inrease of electrical resistivity.
- Mattausch,Simon,Felser
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p. 9951 - 9957
(2007/10/03)
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