bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ethene-trans-1,2-bis(4-pyridinium) Dihydrogenphosphite and Dihydrogenphosphate Compounds Exhibiting Cooperative and Directed Hydrogen Bonds between Cations and Anions: H2bpe(H2PO3)2 and H2bpe(H2PO4)2 · H2O
Authors: Yilmaz Veysel T. , Demir Selcuk , Harrison William T. A. 
Published: February 2015

Abstract
H2bpe(H2PO3)2 (1) and H2bpe(H2PO4)2 ・H2O (2) (H2bpe = ethene-trans-1,2-bis(4-pyridinium), H2PO3 = dihydrogenphosphite, and H2PO4 = dihydrogenphosphate) have been prepared and structurally characterized. In compound 1, the dihydrogenphosphite anions form dimers, with a P···P distance of 4.2073(7) Å , by two O-H···H hydrogen bonds, and the dimeric dihydrogenphosphite units interact with the H2bpe cations by way of N-H···O and O-H···O hydrogen bonds, resulting in a one-dimensional chain. The chains are held together by C-H···O interactions. In compound 2, the phosphate ions are connected by O-H···O hydrogen bonds into an unusual 2D square gridtype framework with P···P separations ranging from 4.7533(7) to 4.9506(8) Å . The H2bpe cations crosslink the dihydrogen phosphate layers by N-H···O hydrogen bonds, forming a three-dimensional supramolecular network with channels. The water molecules in compound 2 occupy these channels and make O-H···O bonds to adjacent phosphate O atoms and also O-H···O bonds to the next water O atom in the channel.
Syntheses, Spectral and Thermal Studies, and Crystal Structure of 1,10-Phenanthroline and Picolinamide Complexes of Cobalt(II) Squarate
Authors: Yeşilel Okan Zafer , Ölmez Halis , Yılan O. Ozan , Paşaoğlu Hümeyra , Büyükgüngör Orhan 
Published: February 2015

Abstract
Preparations, crystal structures, thermal properties, IR and UV/vis spectroscopic studies and magnetic moments of tris(1,10-phenanthroline)cobalt(II) squarate octahydrate, [Co(phen)3]sq ・ 8H2O (1) and diaquabis(picolinamide)cobalt(II) squarate, [Co(H2O)2(pia)2]sq (2) are described. 1 crystallizes in the monoclinic system, space group P21/c, with a = 10.9832(5), b = 21.4569(12), c = 17.0649(7) Å , β = 98.159(3)° and Z = 8, while 2 crystallizes in the triclinic system, space group P1̅, with a =6.9624(9), b =7.9224(11), c =8.0501(11)Å ,α =107.404°, β =93.340(11)°, γ =93.266° and Z = 1. Both 1 and 2 have slightly distorted octahedral coordination geometry, involving six N atoms from bidentately chelating phen ligands and trans-[CoN2O4] coordination geometry, in which the Co atom is located at a center of symmetry. There are significant hydrogen-bonding interactions in the structure of 1. The squarate dianions are linked to the eight solvent water molecules by means of hydrogen-bonding interactions. Moreover, there are links between the complex cation and the squarate dianion via C-H···O hydrogen bonds. These interactions hold the crystal structure of 1 in a three-dimensional network, while O-H···O, N-H···O, weak π ···π and π ··· ring interactions lead to a three-dimensional crystal structure for 2. The thermal decomposition pathways of 1 and 2 have been investigated by the help of thermal analyses data (TG and DTA).
Phase Transitions Mechanism and Distortion of SbCl6
3– Octahedra in Bis(n-butylammonium) Pentachloroantimonate(III) (C4H9NH3)2[SbCl5]
Authors: Zarychta Bartosz , Zaleski Jacek 
Published: February 2015

Abstract
Bis(n-butylammonium) pentachloroantimonate(III) was obtained in a reaction of n-butylammonium chloride and antimony trichloride (molar ratio 2 : 1; cation : Sb) in acidic aqueous solution. To obtain further information about the mechanism of the earlier reported phase transitions at 229 and 315 K the structure was determined at 100, 260 and 340 K. The orthorhombic system was found in all phases, space groups Ibam at 340 K and Pccn at 260 and 100 K. In all phases the anionic sublattice consists of [SbCl6]3− octahedra, connected via cis chlorine atoms, forming onedimensional zig-zag {[SbCl5]2−}n chains extended along the c direction. The n-butylammonium cations are located between the inorganic chains, with -NH3
+ groups facing the oppositely charged polyanions. The phase transitions are of the order-disorder type. They are related to changes in molecular dynamics of the n-butylammonium cations. At high temperature the cations reorient, on decreasing temperature the reorientations are successfully frozen. This leads to the formation on N-H. . .Cl hydrogen bonds, which significantly deform the octahedral coordination of the Sb atoms.
Paullinoside A and Paullinomide A: A New Cerebroside and a New Ceramide from Leaves of Paullinia pinnata
Authors: Miemanang Rénadin Siagat , Krohn Karsten , Hussain Hidayat , Dongo Etienne 
Published: February 2015

Abstract
Paullinoside A (1a), a new cerebroside, and a new ceramide named paullinomide A (2a), have been isolated from Paullinia pinnata. Their structures were determined by comprehensive analyses of their 1D and 2D NMR, HREIMS spectral data, and chemical evidence. The remaining four known compounds were identified as β -amyrin, 13β ,17β -dihydroxy-28-norolean-12-ene, β -sitosterol, and β -sitosterol glucopyranoside.
Synthesis and X-Ray Single Crystal Structure of Dialkyl 2-[1-(2,2-Dimethylpropionyl)-3,3-dimethyl-2-oxobutyl]-3- (triphenylphosphoranylidene)succinates
Authors: Ramazani Ali , Kazemizadeh Ali Reza , Ahmadi Ebrahim , Ślepokura Katarzyna , Lis Tadeusz 
Published: February 2015

Abstract
A one-pot synthesis of sterically congested phosphorus ylides in fairly high yields by the reaction of 2,2,6,6-tetramethyl-3,5-heptanedione, dialkyl acetylenedicarboxylates and triphenylphosphine is reported. The structures of these compounds were confirmed by IR, 1H, 31P and 13C NMR spectroscopy, and X-ray single crystal structure determination. The NMR spectra (CDCl3 as solvent) indicated that the compounds contained two rotamers for each ylide.
Two Prenylated Flavones from the Tree Bark of Artocarpus lanceifolius
Authors: Syah Yana M. , Achmad Sjamsul A. , Aimi Norio , Hakim Euis H. , Juliawatya Lia D. , Takayama Hiromitsu 
Published: February 2015

Abstract
Two new prenylated flavones, artoindonesianins Z-1 (1) and Z-2 (2), together with two other known prenylated flavones, artobiloxantone (3) and cycloartobiloxanthone (4), had been isolated and identified from the chloroform extract of the tree bark of Artocarpus lanceifolius. The structures of these compounds were determined based on spectroscopic data, including UV, IR, 1-D and 2-D NMR, and mass spectra. The significance of the presence of the isolated compounds to the chemotaxonomy of Artocarpus is briefly discussed.
Synthesis of Some 2-Aminonitroethanes via Silica Gel-Catalyzed Nitro-Mannich Reaction
Authors: Mahasneh Ali S. 
Published: February 2015

Abstract
A direct one pot, three-component nitro-Mannich reaction of a nonenolizable aldehyde, aniline or one of its ring-substituted derivatives and nitromethane was carried out on silica gel surface. The products of the reaction, 2-aminonitroethane, were obtained in high yields. IR, 1H NMR, 13C NMR spectra and elemental analysis confirmed the structures of the products.
The Reactions of Some Alkyl(thio)-Substituted 2-Nitrodienes with Piperazines and a Structural Study
Authors: Ibis Cemil , Sayil Cigdem , Ozkok Funda 
Published: February 2015

Abstract
Thiosubstituted nitrodiene compound 1a was obtained from 2-nitropentachlorobutadiene and dodecanethiol. Compound 1b was prepared from 2-nitropentachlorobutadiene and hexadecanethiol. Monosubstituted diene compounds 1a and 1b reacted with piperazines such as derivatives of 2 and 4 in CH2Cl2 and gave the novel compounds. 2-Nitro-3,4,4-trichloro-1-dodecylthio-1-(2-fluorophenylpiperazinyl]- 1,3-butadiene (3d) was synthesized and its crystal structure was determined.
Acylated Iridoid Glycosides from the Flowers of Verbascum lasianthum Boiss. ex Bentham
Authors: Tatli I. Irem , Khan Ikhlas A. , Akdemir Zeliha S. 
Published: February 2015

Abstract
Two new (1 - 2) and five known iridoid glycosides (3 - 7) as well as a known saponin (8) were isolated from the flowers of Verbascum lasianthum and their structures were determined as 6-O-(4"-O-trans-p-coumaroyl)-α-L-rhamnopyranosylaucubin (1), 6-O-(4"-O-trans-p-methoxycinnamoyl)- α-L-rhamnopyranosylaucubin (2), sinuatol (3), aucubin (4), geniposidic acid (5), catalpol (6), ajugol (7) and ilwensisaponin A (8) on the basis of 1D and 2D NMR spectral analysis.
Kinetics of the Oxidation of L-Cysteine by trans- and cis-Cobalt(III) and Iron(III) Complexes
Authors: Abdel-Halim Hamzeh M. , Abu-Surrah Adnan S. , Baker Hutaf M. 
Published: February 2015

Kinetics of oxidation of L-cysteine by pairs of trans and racemic cis isomers of cobalt(III) and iron(III) based transition metal complexes have been studied in aqueous solution. Kinetics measurements were run under pseudo first order conditions in which the concentration of cysteine is between one and two orders of magnitude greater than that of the isomers of the transition metal complex. The orders of the reaction with respect to both cysteine and the isomer were determined.
The observed rate constants and the overall rate constants of the oxidation process were measured. For all geometrical isomers, it was found that the rate constant of oxidation of L-cysteine by the trans isomer is between one to three orders of magnitude greater than that by the cis isomer. The difference in rates can be explained by a geometric factor around the metal ion center in the complex. The less crowded isomer (trans) makes electron transfer easier and hence facilitates the oxidation process which leads to a higher oxidation rate.
Syntheses of Allyl- and 3-Silylpropyl-substituted Salen-like Tetradentate Ligands via Hypercoordinate Silicon Complexes
Authors: Wagler Jörg , Roewer Gerhard 
Published: February 2015

The reaction of allylchlorosilanes (AllSiCl3, AllSiPhCl2) with the tetradentate salen-like ligand 1, o-HO-p-MeO-C6H3-C(Ph)=N-(CH2)2-N=C(Ph)-C6H3-p-OMe-o-OH, yields pentacoordinate silicon complexes of an allyl-substituted ligand system (o-O-p-MeO-C6H3-C(Ph)=N-(CH2)2- N-C(Ph,All)-C6H3-p-OMe-o-O)SiR (2a: R = Ph, 3: R = Cl). The allyl shift step involved in the formation of 2a and 3 probably occurs via an intermediate hexacoordinate silicon complex. This reaction is diastereoselective. The missing diastereomer of 2 (2b) was prepared using an alternative synthesis route, which starts from the trimethylsilyl derivative of ligand 1 o-Me3SiO-p-MeO-C6H3-C(Ph)=N- (CH2)2-N=C(Ph)-C6H3-p-OMe-o-OSiMe3. The diastereomers of 2 obtained from modified reaction pathways give rise to suggestions about the mechanism of formation of these complexes.
Further functionalization of the allyl-substituted ligand system of 3 was carried out by hydrosilylation with HSiCl3 to yield complex 4 (o-O-p-MeO-C6H3-C(Ph)=N-(CH2)2-N-C(Ph)[(CH2)3-SiCl3]- C6H3-p-OMe-o-O)SiCl.
Kristallstruktur und Eigenschaften von Chrom(II)-Tetrachloroaluminat/Crystal Structure and Properties of Chromium(II)-Tetrachloroaluminate
Authors: Müller Rainhard , Vajenine Grigori V. , Keßler Ulrich 
Published: February 2015

Abstract
Chromium(II)tetrachloroaluminate can be prepared by reaction of chromium, chromium trichloride and aluminum trichloride in the molar ratio 1 : 1.94 : 5.79 or by reaction of stoichiometric amounts of chromium dichloride and aluminum trichloride. Sublimation of the compound yields phase-pure samples of colourless crystals. Cr(AlCl4)2 crystallizes in the non-centrosymmetric orthorhombic space group Pca21 (No. 29), a = 1511.38(3), b = 604.71(1), c = 1301.76(3) pm. The aggregation of Cr(AlCl4)2 molecules leads to a square-bipyramidal coordination of the chromium atom typical of high-spin d4 ions due to the Jahn-Teller effect. The relationship to centrosymmetric Pd(AlCl4)2 (P21/c) which is built up of similar molecules was established by means of a group-subgroup symmetry tree. The temperature dependence of the magnetic susceptibility agrees with Curie-Weiss behaviour (μeff = 4.70 μB,Θ = −1.3 K).
Rare Earth-rich Magnesium Compounds RE4RhMg (RE = Y, La–Nd, Sm, Gd–Tm, Lu)
Authors: Tuncel Selcan , Rodewald Ute Ch. , Chevalier Bernard , Pöttgen Rainer 
Published: February 2015

Abstract
The series of magnesium compounds RE4RhMg (RE = Y, La-Nd, Sm, Gd-Tm, Lu) was prepared by high-frequency melting of the elements in sealed tantalum tubes. All samples were investigated by powder X-ray diffraction. The structures with RE = Sm, Gd, Dy, Ho, and Er as rare earth metal components were refined from single crystal diffractometer data: Gd4RhIn-type, F4̄3m, Z = 16, a = 1392.1(1) pm, wR2 = 0.060, 616 F2 values, 19 variables for Sm4RhMg, a = 1380.8(2) pm, wR2 = 0.071, 530 F2 values, 19 variables for Gd4RhMg, a = 1366.9(1) pm, wR2 = 0.070, 594 F2 values, 20 variables for Dy4RhMg, a = 1355.7(2) pm, wR2 = 0.077, 578 F2 values, 20 variables for Ho3.52RhMg1.48, and a = 1355.4(2) pm, wR2 = 0.075, 559 F2 values, 20 variables for Er3.94RhMg1.06 .The rhodium atoms have slightly distorted trigonal prismatic rare earth coordination. Condensation of the RhRE6 prisms leads to a three-dimensional network which leaves large voids that are filled by regular Mg4 tetrahedra with a Mg-Mg distance of 312 pm in Sm4RhMg. The magnesium atoms have twelve nearest neighbors (3 Mg + 9 RE) in icosahedral coordination. In the structures with holmium and erbium, the RE1 positions which are not involved in the trigonal prismatic network exhibit RE1/Mg mixing. Shortest distances occur for Sm-Rh (286 pm) within the rigid three-dimensional network of condensed trigonal prisms.
Synthesis, Crystal Structure and Optical Spectra of Yb2[CN2]3
Authors: Reckeweg Olaf , Schleid Thomas , DiSalvo Francis J. 
Published: February 2015

Abstract
Red-orange, transparent single crystals of Yb2[CN2]3 [trigonal, R3̄c (no. 167), a = 630.02(3) and c = 2947.4(2) pm, Z = 6] are obtained by the reaction of Yb, Sn, Zn[CN2] and NaN3 in arc-welded Nb ampoules at 1100 K. The title compound exhibits characteristic C-N bond lengths and angles [d(C-N) = 122.7(3) pm and ∡(N-C-N) = 178.4(5)°, respectively] within the [N=C=N]2− unit as well as the expected fundamental frequencies in its optical spectra (Raman: νs = 1338; δ = 643 / 683 / 695 cm−1; IR: νas = 2005 / 2037; δ = 640 / 679 cm−1). Since Yb2[CN2]3 adopts a corundum-type structure, Yb3+ is octahedrally coordinated by six N atoms of different [CN2]2− anions [d(Yb-N) = 228.6(3) and 233.4(3) pm, 3× each] and every [CN2]2− group has four Yb3+ as next neighbours which form a distorted tetrahedron.
Effect of High-energy Milling on the Solid State Formation of Zinc Manganites (ZnxMn3-xO4, 0.5 ≤ x ≤ 1.5) from the System ZnC2O4 · 2H2O-n MnCO3 (n = 1, 1.5 and 2)
Authors: Berbenni Vittorio , Milanese Chiara , Marini Amedeo 
Published: February 2015

Abstract
By combination of TG/DSC and XRPD measurements it has been shown that zinc manganites form (ZnxMn3−xO4 with 0.5 ≤ x ≤ 1.5) starting from mixtures of zinc oxalate dihydrate and manganese carbonate subjected to mechanical activation by high energy milling. Solid solutions ZnOMn3O4- ZnMn2O4 are the products obtained by the same experimental conditions, when starting from a physical mixture. Furthermore milling, besides changing the enthalpy of dehydration of zinc oxalate, induces a partial formation of amorphous Mn3O4 at r. t. In particular ZnMn2O4 can be prepared by annealing the milled mixture for 18 h at 650 °C while a temperature > 1000 °C is needed to prepare ZnMn2O4 from a physical mixture. Finally, the calorimetric data suggest that the mechanism of the reaction is different in the two kinds of mixtures.
Syntheses and Structures of Two Arene-Ruthenium(II) Complexes with Cyclometalating 2-Pyridyl-m-tolyl Ligands
Authors: Zhang Xiu-Zhen , Yao Wen-Rui , Zhang Qian-Feng , Leung Wa-Hung 
Published: February 2015

Abstract
Reactions of [(η6-C6Me6)RuCl2]2 and [(η6-p-cymene)RuCl2]2 with [Hg(ptpy)2] (Hptpy = 2-pyridyl-m-toluene) in THF afforded [{(η6-C6Me6)Ru(ptpy)}2(μ-Hg2Cl6)] 1 and [(η6-pcymene) Ru(ptpy)(HgCl3)] 2, respectively. The crystal structures of complexes 1 and 2 have been determined by single-crystal X-ray diffraction. The ruthenium atom in both molecules 1 and 2 adopts a pseudo octahedral configuration containing a cyclometalated ptpy ligand. The Ru−C(ptpy) and Ru−N bond lengths in 1 are 2.049(3) and 2.089(2) Å, respectively. The corresponding bond lengths for 2 are 2.025(9) and 2.089(7) Å .
A Spectroscopic and Kinetic Investigation on the Substitution of Fe(III) for Ni(II) in a Siderophore Model
Authors: Barreto Wagner J. , Silva Waléria P. , Scarmínio Ieda S. , Barreto Sônia R. Giancoli , Silva Luís F. Stucchi 
Published: February 2015

Abstract
A kinetic and spectroscopic study was performed on the substitution of Fe(III) by Ni(II) in the water soluble anion [Fe(L1−)2L2−]−, a siderophore model (L− = dopa-semiquinone and L2− = dopacatecholate). The reaction was followed in the UV/vis range through the appearing of an intense band at 592 nm due to the anion complex [Ni(L1−)3]− formed which also presents a resonance Raman effect. The overall reaction obeyed a zero-order rate law at 25, 35, 45, and 50 °C, and the rate constants and thermodynamic parameters have been obtained. A chemometric study based on the Imbrie Q-type factor analysis revealed that the reaction occurred with only one kind of intermediate whose UV/vis spectrum has been calculated.
A Novel Hydrogen-bonded Zigzag Chain Manganese(III) Complex: Synthesis, Crystal Structure and Magnetic Properties
Authors: Kara Hulya 
Published: February 2015

Abstract
The synthesis, crystal structure and magnetic properties of [Mn(III)L(H2O)2]+ClO4 −, 1 [L = N,N′-bis(rac-3,5-dichlorosalicylidenato)-1,2-diaminopropane] are reported. Single crystal X-ray diffraction studies showed the structure to consist of [MnL(H2O)2]+ octahedra, with trans-coordinated water molecules, which are linked into infinite helices by hydrogen bonds. The distorted octahedral manganese(III) centre contains an N2O2O′2 coordination sphere made up of the Schiff base ligand in the equatorial plane. In the axial direction, an elongation of the trans Mn-Owater bonds to 2.165(2) and 2.187(2) Å is observed. Such elongations are typical of d4 systems but in this case may also be attributed to the poorer donor power of the water molecules.
One-pot Green Synthesis for Pyrimido[4,5-d]pyrimidine Derivatives
Authors: Kidwai Mazaahir , Singhal Kavita , Kukreja Shuchi 
Published: February 2015

Abstract
Water has been used efficiently as a solvent for the reaction of barbituric acid, aldehyde and urea or thiourea to yield pyrimido[4,5-d]pyrimidines. This environmentally benign procedure leads to high yields of products of greater purity in a single step using water.
Crystal Structures of New Pyrovanadates A2MnV2O7 (A = Rb, K)
Authors: Yahia Hamdi Ben , Gaudin Etienne , Darriet Jacques 
Published: February 2015

Abstract
The new compounds A2MnV2O7 (A = K, Rb) with structures related to the melilite-type have been synthesized by a solid state reaction route. The crystal structures of K2MnV2O7, Rb2MnV2O7 and KRbMnV2O7 have been determined using X-ray single crystal diffraction data. The compound K2MnV2O7 crystallizes with a melilite-type structure with tetragonal unit cell parameters a = 8.609(3), c = 5.538(4) Å and space group P4̅21m. The structures of Rb2MnV2O7 and KRbMnV2O7 are derived from the melilite-type structure with space group P4̅2/mnm and unit cell parameters a = 8.577(6), c = 11.809(6) Å , and a = 8.530(6), c = 11.466(5) Å , respectively. The three structures consist of [MnV2O7]2− layers perpendicular to the c axis separated by A+ layers. The [MnV2O7]2− layers feature corner-sharing MnO4 tetrahedra and V2O7 pyrovanadate units, the linkage leading to rings of five tetrahedra. The doubling of the c parameter for Rb2MnV2O7 or RbKMnV2O7 is explained by the existence of a mirror plane perpendicular to the [001] direction between two [MnV2O7]2− layers. The A+ alkali cations occupy distorted square antiprisms of oxygen atoms in K2MnV2O7 and distorted square prisms of oxygen atoms in Rb2MnV2O7and RbKMnV2O7.
Magnetic Properties and Specific Heat Studies of the Plumbides CeTPb (T = Cu, Pd, Ag, Au)
Authors: Hermes Wilfried , Rayaprol Sudhindra , Pöttgen Rainer 
Published: February 2015

Abstract
The cerium plumbides CeCuPb, CePdPb, CeAgPb, and CeAuPb have been synthesized from the elements in sealed tantalum tubes in a high-frequency furnace followed by annealing. The copper, silver and gold compounds crystallize with the NdPtSb-type structure, space group P63mc: a = 466.1(2), c = 778.1(3) pm for CeCuPb, a = 484.8(2), c = 773.0(3) pm for CeAgPb, and a = 480.24(9), c = 772.9(2) pm for CeAuPb. CePdPb crystallizes with the ZrNiAl-type structure: P6̅2m, a = 775.0(2), c = 413.32(8) pm. The dc susceptibility measurements show trivalent cerium for all four plumbides with experimental magnetic moments of 2.53(2), 2.71(2), 2.63(2), and 2.58(2) μB/Ce atom for CeCuPb, CePdPb, CeAgPb, and CeAuPb, respectively. The compounds CeCuPb, CeAgPb, and CeAuPb, studied by dc susceptibility and specific heat measurements, order antiferromagnetically at N´eel temperatures of 8.2(1), 7.4(1), and 3.7(1) K, respectively.
Magnesium Hydride: From the Laboratory to the Tank
Authors: Roquefere Jean-Gabriel , Bobet Jean-Louis 
Published: February 2015

Abstract
Magnesium metal is under extensive study for its high hydrogen absorption capacity. The main results obtained by the authors, going from the effects of ‘reactive mechanical grinding’ to the addition of nano oxides or to the deposition of nanoparticles are reported and discussed. The absorption properties are compared with the results of other research groups. An improvement of kinetics has been achieved and the mechanisms of the hydrogenation reaction is almost fully understood, but the effects of catalysts are still subject to hypotheses. Recent developments of MgH2 tanks are also presented.
Hydriding Properties of MgH2-Mg2Ni0.8Co0.2 Composites Obtained by Ball Milling
Authors: Mandzhukova Tsveta , Bobet Jean-Louis , Khrussanova Maria , Peshev Pavel 
Published: February 2015

Abstract
The hydrogen absorption-desorption characteristics of composites consisting of 90 wt.% MgH2- 10 wt.% Mg2Ni0.8Co0.2 prepared by ball milling for 30 and 180 min under argon have been investigated. The results obtained have been compared with those for the 90 wt.% Mg-10 wt.% Mg2Ni0.8Co0.2 composite synthesized in the same medium after 30 min of milling. The presence of the Mg2Ni0.8Co0.2 phase has been found to improve the hydriding kinetics of magnesium, the absorption capacity remaining high at temperatures below 573 K. The use of magnesium hydride instead of magnesium has proved to have a favorable effect on the properties of the composites after prolonged activation in an inert medium. It has been established that the absorption-desorption characteristics of the composite 90 wt.% MgH2-10 wt.% Mg2Ni0.8Co0.2 activated mechanically for 180 min are comparable with those of the composite 90 wt.% Mg-10 wt.% Mg2Ni0.8Co0.2 after mechanical activation for only 30 min. The favorable absorption-desorption characteristics of the composites have been explained with the catalytic effect of the additive, the presence of magnesium hydride and the duration of ball milling.
Chemical Bonding and Physical Properties of Yb5Bi3
Authors: Liang Ying , Cardoso-Gil Raul , Schnelle Walter , Schmidt Marcus , Zhao Jing Tai , Grin Yuri 
Published: February 2015

Abstract
The binary compound Yb5Bi3 was synthesized by reaction of the elements in a sealed Ta container. Its crystal structure was determined from single-crystal X-ray diffraction data: β -Yb5Sb3-type, space group Pnma, Pearson code oP32, a = 12.6375(6), b = 9.7243(4), c = 8.4117(5) Å, V = 1033.72(9) Å3, Z = 4, Rgt(F) = 0.028, wRref(F2) = 0.069, T = 290 K. Band structure calculations and analysis of the chemical bonding suggest mainly ionic interactions in the crystal structure and a possible presence of ytterbium in two valence states Yb2+ and Yb3+. The magnetization measurements showed that at low temperatures Yb5Bi3 contains ytterbium exclusively in the 4f14 configuration without fluctuations to the Yb 4f13 configuration up to 400 K. From the Yb-LIII X-ray absorption spectroscopy data the effective valence of ytterbium was found to be 2.11 (89% of Yb in 4f14 configuration).