Der chemische Transport von Ni3Ge,Ni5Ge3, Ni(Ge)-Mischkristall,CoSn, Co3Sn2, Cu41Sn11 (δ-Phase), Cu10Sn3 (ζ-Phase) und Cu(Sn)-Mischkristall

Chemical Vapour Transport of Intermetallic Systems. 7. Chemical Transport of Ni₃Ge, Ni₅Ge₃, Ni(Ge)-mixed Crystal, CoSn, Co₃Sn₂, Cu₄₁Sn₁₁ (δ-phase), Cu₁₀Sn₃ (ζ-phase), and Cu(Sn)-mixed Crystals By means of GaI₃ as transport agent some intermetallics in the Ni/Ge- and Co/Sn-system can be prepared by CVT-methods. Using Iodine Cu–Sn-compounds can be deposited in a similiar way.     

The Crystal Structure of Ni21Sn2P6

During an investigation of the phase equilibria in the ternary system Ni/P/Sn, the existence of a new phase Ni₂₁Sn₂P₆ with a composition close to the known Ni₁₀P₃Sn phase was found. The crystal structure of the new phase was determined using single crystal X‐ray diffraction. The structure was solved employing Patterson and Difference Fourier Analysis. Ni₂₁P₆Sn₂ (space group , a = 1112.2 pm) crystallizes in an ordered variant of the C₆Cr₂₃ structure common to many carbides, borides and phosphides. The relation between Ni₂₁Sn₂P₆ and other C₆Cr₂₃ type phases and to Ni₁₀P₃Sn was established.     

Ni2Sn2Zn from single‐crystal X‐ray diffraction

Dinickel ditin zinc, Ni₂Sn₂Zn, crystallizes in the cubic space group , with a lattice parameter of a = 8.845 (1) Å and with all atoms occupying special positions. The crystal structure exhibits pronounced similarities with that of the quaternary compound Ni_5.20Sn_8.7Zn_4.16Cu_1.04. It shares structural features with other compounds in the Ni–Sn–Zn system, such as Ni₅Sn₄Zn and Ni₃Sn₂.     

The Valence States of Nickel,Tin, and Sulfur in the Ternary Chalcogenide Ni3Sn2S2—XPS, 61Ni and 119Sn Mössbauer Investigations,and Band Structure Calculations

The hitherto controversial valence states of nickel and tin in the ternary chalcogenide Ni₃Sn₂S₂ (see structure) have been determined by photoelectron and Mössbauer spectroscopy (⁶¹Ni, ¹¹⁹Sn). Results from band structure calculations confirmed that this shandite phase is a metal and that the approximate distribution of the valence electrons is (Ni⁰)₃(Sn(1)^II)(Sn(2)^II)(S^II−)₂.     

Reaction of Ni2+ and SnS as a Way to Form Ni@SnS and Sn2Ni3S2 Nanocrystals: Control of Product Formation and Shape

Reductive diffusion of Ni²⁺ into SnS particles was shown to selectively form Sn₂Ni₃S₂, hybrid, or even core‐shell Ni@SnS, Ni_1.523Sn, and Ni₃S₂, by tuning the reaction conditions at low temperatures. The mechanism of Ni²⁺ reduction and diffusion into SnS was observed in ethylene glycol, which served both as solvent and reducing agent. Tuning of reaction temperature and duration, morphology of the template SnS, and the application of ethylenediamine as supporting chelating agent, influence the formation of the final products. Their formation was controlled by carefully adjusting redox and equilibrium reactions. The products were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X‐ray spectroscopy analysis (EDX).     

新型的钛基Ni-Sn/Ti电极的制备及对甲醇氧化反应的电催化活性

利用电热法,一步制备出新型的钛基Ni-Sn/Ti电极(Ni8Sn/Ti, Ni7Sn3/Ti 和 Ni/Ti)。扫描电镜（SEM）图像表明,催化剂以片状的纳米颗粒形式沉积于钛基体上。利用电化学伏安技术、电位阶跃法和电化学交流阻抗谱（EIS）,研究了这些电极在1mol.L�1NaOH溶液中对甲醇氧化反应的电催化活性。研究表明,与Ni7Sn3/Ti,Ni/Ti以及多晶镍电极相比,Ni8Sn/Ti电极对甲醇氧化反应表现出更高的阳极氧化电流和更低的起始电位。EIS分析表明,在本文所考察的阳极电位和甲醇浓度下,Ni8Sn/Ti电极对甲醇氧化反应显示出极低的电荷传递电阻。结果表明,这种新型的钛基Ni8Sn/Ti电极对甲醇氧化反应具有极高的电催化活性。     

Single Crystal X‐ray Structure Investigation and Electronic Structure Studies of La‐Deficient Nickel Stannide La4.87Ni12Sn24 Grown from Sn Flux

The cubic La_4.87Ni₁₂Sn₂₄ was synthesized in reactions involving liquid Sn. The compound crystallizes in the cubic syngony, space group Im3¯, Z = 2, cell parameter a = 11.9662(14) Å, and is related to the Gd₃Ni₈Sn₁₆ structure type previously refined from powder X‐ray data. The crystal structure of La_4.87Ni₁₂Sn₂₄ was solved and refined using single crystal X‐ray data to final R₁ = 2.67%, wR₂ = 6.92%. The refinement showed no mixed occupancy with Sn for the La(1) site, contrary to what was proposed for Gd₃Ni₈Sn₁₆. Instead, a partial occupancy of 87% was detected for the La(1) at 2a. Electronic structure calculations show that the system is metallic, and the density of states at the Fermi level falls at a peak with the highest contribution coming from La(1) atoms, if the compound with ideal occupancies La₅Ni₁₂Sn₂₄ is assumed. The deficiency of the La(1) site could therefore originate in the lowering of the total energy of the system due to the loss of 0.39 electrons per formula unit. Magnetic measurement data indicates nearly temperature independent Pauli paramagnetism. Theoretical estimation of the magnetic susceptibility after including core diamagnetic corrections agrees well with experiment.     

New refinement of Ni5.20Sn8.7Zn4.16Cu1.04 and its non‐isotypy with Ni2Sn2Zn

The noncentrosymmetric space group P3m but a pseudocentric cubic crystal structure were reported for the compound Ni_5.20Sn_8.7Zn_4.16Cu_1.04 [Larsson et al. (1994). Acta Cryst. C 50 , 9–12]. The recently described Ni₂Sn₂Zn shows a closely related structure, although it is centrosymmetric and contains additional voids which are partially occupied. Therefore, a new refinement of Ni_5.20Sn_8.7Zn_4.16Cu_1.04 based on the originally published structure factors was performed. The results indicate that the structure can indeed be described in the centrosymmetric space group Pmm; no justification for the absence of the inversion centre could be found within the accuracy of the available data. In comparison with Ni₂Sn₂Zn, slight but significant differences were confirmed; consequently, the two structures are topologically related but not isotypic.     

Ni5‐δSn4Zn (δ ∼ 0.25) from single‐crystal data

Work on the ternary Ni–Sn–Zn phase diagram revealed the existence of the title compound pentanickel tetratin zinc, Ni_3.17Sn_2.67Zn_0.67 [Schmetterer et al. (2012). Intermetallics, doi:10.1016/j.intermet.2011.05.025]. It crystallizes in the Ni₅Ga₃Ge₂ structure type (orthorhombic, Cmcm) and is related to the InNi₂ type (hexagonal, P6₃/mmc) of the neighbouring Ni₃Sn₂ high‐temperature (HT) phase, but is not a superstructure. The crystal structure was determined using single‐crystal X‐ray diffraction. Its homogeneity range was characterized using electron microprobe analysis. Phase analysis at various temperatures indicated that the phase decomposes between 1073 and 1173 K, where a more extended ternary solid solution of the Ni₃Sn₂ HT phase was found instead.     

Chemischer Transport fester Lösungen. 8 [1] Zum Chemischen Transport von ternären und quaternären Cobalt(II)‐ und Nickel(II)‐germanaten

Chemical Vapor Transport of Solid Solutions. 8 The Chemical Vapor Transport of Ternary and Quarternary Cobalt and Nickel Germanates By means of chemical vapor transport methods using HCl as transport agent CoGeO₃, Co₂GeO₄, and Ni₂GeO₄ have been prepared (1000 → 900 °C and 900 → 700 °C). In this system the formation of a continuous crystalline solid solution of Co₂GeO₄ and Ni₂GeO₄ was found as well as the deposition of the compound NiGeO₃ which — although unknown as a pure solid — can be stabilized as a mixed crystal Ni_xCo_1—xGeO₃ (0 < x < 0, 6).     

ChemInform Abstract: The Crystal Structures of Ni3+xSn4Zn and Ni6+xSn8Zn and Their Structural Relations to Ni3+xSn4, NiSn and Ni5‐δZnSn4.

Two new compounds, Ni_3+xSn₄Zn (x≈1.35, monoclinic, space group I2/m, Z = 2, single crystal XRD) and Ni_6+xSn₈Zn (x≈1.35, monoclinic, space group C2/m, Z = 2) are prepared by solid state reaction of the elements (Al₂O₃ crucible in evacuated quartz tubes, 1453 K).     

Darstellung,Eigenschaften und Phasenbeziehungen von Ru3Sn15O14

Preparation, Properties, and Phase Relations of Ru₃Sn₁₅O₁₄ Coexistence relations in the system Ru/Sn/O have been investigated by X‐ray measurements of powder mixtures annealed in the region of 1173–1273 K. Thermodynamic data of Ru₂Sn₃, Ru₃Sn₇, and Ru₃Sn₁₅O₁₄ were obtained by EMF measurements. Phase diagrams calculated with these data are in good agreement with experimental results. Only one phase, Ru₃Sn₁₅O₁₄, exists in the ternary system between 973 and 1273 K. Red translucend single crystals were obtained from a tin melt. Polycrystalline powder was prepared by solid state reaction of a mixture of Ru₃Sn₇, SnO₂, and Sn with molar ratio 1:7:1 at 1173 K. Ru₃Sn₁₅O₁₄ is a p‐type semiconductor, E_A = 0.50(5) eV, as conductivity and thermopower measurements show. Mössbauer investigations confirm the existence of three different tin surroundings.     

Chemischer Transport intermetallischer Phasen. 4. Der chemische Transport von Co5Ge3 und CoGe

Chemical Vapor Transport of Intermetallic Systems. Chemical Transport of Co₅Ge₃ and CoGe By means of transport reaction (900 → 700°C, Iodine as transport agent) pure Co₅Ge₃ or Co₅Ge₃ with CoGe as a by-product can be prepared. Thermodynamic calculations allow to understand the reaction semiquantitatively.     

Martensitic transformation in Mn–Ni–Sn Heusler alloys

Three magnetic shape memory alloys: Mn₅₀Ni_50−x Sn _x (x = 5, 7.5, and 10) were produced as bulk polycrystalline ingots by arc melting. The structural austenite–martensite transformation was checked by calorimetry. The transformation temperatures decrease as increasing the Sn content. The same trend is found in the entropy and enthalpy changes related to the transformation. The control of the valence electron by atom e/a determines the transformation temperatures range in this kind of alloys and it is possible to develop alloys that can be candidates in applications as sensors and actuators. Furthermore, X-ray diffraction was performed to check the crystalline structure at room temperature.     

Chemischer Transport intermetallischer Phasen. 3 [1]. Der chemische Transport von Mischkristallen im System Mo/W

Chemical Vapor Transport of Intermetallic Systems. 3. Chemical Transport of Mo/W-mixed Crystals Mo/W-mixed crystals can be prepared by means of chemical vapor transport with HgBr₂ (1000°C→900°C). It is known [2] that the transport reaction of tungsten begins hours or even days after starting the experiment. This is the reason for the unusual composition of deposited crystals: EDX-analysis show them to have a Mo-rich nucleus and a W-rich shell.     

Rationally Modulating the Functions of Ni3Sn2-NiSnOx Nanocomposite Electrocatalysts towards Enhanced Hydrogen Evolution Reaction

Identifying electrocatalysts with functions of easy dissociation of water, rapid transformation of hydroxyl and facile hydrogen-hydrogen bond formation are indispensable while challenge for realizing efficient alkaline hydrogen evolution reaction (HER). Herein, we presented the design of Ni₃Sn₂-NiSnO_x nanocomposites towards addressing this challenge. We showed that Ni₃Sn₂ possessed ideal hydrogen adsorption and low hydroxyl adsorption abilities and NiSnO_x facilitated water dissociation and hydroxyl transfer process, respectively. Consequently, the fine-tuned interplay of the two functional parts realized the mutual coordination among the multiple functions and led to significantly boosted HER kinetics. Current densities of 10 and 1000 mA cm⁻² were obtained at overpotentials of 14 and 165 mV on the optimized catalyst. This work highlights the significance of considering intrinsic interactions between active sites and all pertinent intermediates on obtaining promising electrocatalysts.     

Mössbauer-Messungen an Sn2O3

Mössbauer Studies on Sn₂O₃ Mössbauer data for ¹¹⁹Sn in Sn₂O₃ show this compound to contain bivalent and tetravalent tin. Whereas tin(IV) is coordinated in a similar way in Sn₂O₃ and SnO₂, a rather large quadrupole splitting indicates an environment of low symmetry for tin(II).     

Phasenbeziehungen im System LiGa?Sn und die Kristallstrukturen der intermediären Phasen LiGaSn und Li2Ga2Sn

Phase Relations in the System LiGa? Sn and the Crystal Structures of the Intermediate Compounds LiGaSn and Li₂Ga₂Sn The quasibinary system LiGa? Sn contains the intermediate ternary phases Li₇Ga₇Sn₃, Li₂Ga₂Sn, Li₅Ga₅Sn₃, Li₃Ga₃Sn₂ and LiGaSn. Single crystals of LiGaSn (a = 632.9(4) pm, Fd3m, Z = 4), Li₃Ga₃Sn₂ (a = 445.4(3), c = 1 090.0(2) pm, hP*), Li₅Ga₅Sn₃ (a = 447.0(4), c = 4 220.0(9) pm, hP*) and Li₂Ga₂Sn (a = 441.1(2), c = 2 164.5(7) pm, P6₃/mmc, Z = 4) have been grown from the melt. The crystal structures of LiGaSn and Li₂Ga₂Sn have been determined by single crystal X-ray methods (R = 0.029 bzw. 0.107 respectively). The crystal structure of LiGaSn contains a sphalerite-type Ga/Sn-arrangement, the Ga/Sn-arrangement of Li₂Ga₂Sn corresponds to a stacking variant of the wurtzite- and sphalerite-type. The compounds can be classified in terms of the Zintl concept.     

Promotional effect of Snad on the ethanol oxidation at Pt3Sn/C catalyst

Oxidation of ethanol was studied at Sn_ad modified and unmodified Pt₃Sn/C and Pt/C catalysts. Pt₃Sn/C and Pt/C catalysts were characterized by XRD. Potentiodynamic and chronoamperometric measurements were used to establish catalytic activity and stability. High activity achieved at Sn_ad modified Pt₃Sn/C catalyst has not been observed at any bimetallic catalyst so far. Promotional effect of Sn_ad on the ethanol oxidation was related to the enhancement of CO oxidation rate in bifunctional mechanism. It was shown that electrodeposited Sn exhibited different effect on the catalytic activity compared to Sn in alloy.