- Preparation and crystal structure of the copper silicon polyphosphide Cu4SiP8
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The new compound Cu4SiP8 was prepared by solid state reaction of the elemental components. It crystallizes with a new structure type, which was determined from single-crystal X-ray diffractometer data: I41/a, a = 1218.6(2)pm, c = 573.2(2) pm, Z = 8, R = 0.023 for 970 structure factors and 31 variable parameters. Tetrahedral SiP4 groups are linked via additional phosphorus atoms to a three-dimensionally infinite silicon phosphorus network, accommodating Cu2 pairs with octahedral phosphorus coordination as is known for the closely related structure of CuP2. Using oxidation numbers the compound may be rationalized by the formula (Cu+1)4Si+4(P0)4(P -2)4 in agreement with the Zintl-Klemm concept. Johann Ambrosius Barth 1996.
- Kaiser, Peter,Jeitschko, Wolfgang
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- Low-Temperature Tailoring of Copper-Deficient Cu3- xP - Electric Properties, Phase Transitions, and Performance in Lithium-Ion Batteries
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A convenient approach for a controlled and high-yield synthesis of copper-deficient Cu3-xP (0.1 3-xP shows a high degree of tolerance for cation vacancies without major structural reorganization, as evidenced by X-ray diffraction and solid-state nuclear magnetic resonance spectroscopy. Measurements of the electric properties reveal that Cu3-xP is a bad metallic p-type conductor. The resistivity is composition-dependent and displays a distinct anomaly from a phase transition, leading to the discovery and structural characterization of two hitherto unknown low temperature polymorphs. Electrochemical evaluation of copper-deficient Cu3-xP as anode material for lithium ion batteries reveals a drastic change in the cycling mechanism leading to an increase of the initial capacities by about 70%. This work gives a comprehensive insight into the chemical and structural features of copper-deficient Cu3-xP and should lead to an improved understanding of its properties, not just for battery applications.
- Wolff, Alexander,Doert, Thomas,Hunger, Jens,Kaiser, Martin,Pallmann, Julia,Reinhold, Romy,Yogendra, Sivatmeehan,Giebeler, Lars,Sichelschmidt, J?rg,Schnelle, Walter,Whiteside, Rachel,Gunaratne, H. Q. Nimal,Nockemann, Peter,Weigand, Jan J.,Brunner, Eike,Ruck, Michael
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- Solution-liquid-solid growth of ternary Cu-In-Se semiconductor nanowires from multiple- and single-source precursors
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Ternary CuInSe2 nanowires were synthesized for the first time by the solution-liquid-solid (SLS) mechanism. Here, both metal-organic multiple- and single-source molecular precursors were thermally decomposed in the presence of molten metal nano
- Wooten, Alfred J.,Werder, Donald J.,Williams, Darrick J.,Casson, Joanna L.,Hollingsworth, Jennifer A.
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- PREPARATION, PROPERTIES, AND CRYSTAL STRUCTURE OF THE SOLID ELECTROLYTES Cu2P3I2 AND Ag2P3I2.
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The new compound Cu//2P//3I//2 is a diamagnetic semiconductor with a susceptibility of chi equals minus 193 multiplied by 10** minus **6 cm**3/ mole and a band gap of E//a equals 0. 72 ev. Its crystal structure is monoclinic, space group P2//1/c, with the lattice constants a equals 15. 343(2) A, b equals 12. 925(2) A, c equals 15. 260(2) A, beta equals 116. 38(1) degree , and Z equals 16 formula units per cell. Twinning wrongly suggests orthorhombic and tetragonal symmetry. The crystal structure was determined from single-crystal X-ray data and refined to a residual of R equals 0. 068 and 4330 independent structure factors and 197 variable parameters. The P atoms form tubes similar to those in the Hittorf modification of phosphorus. They are surrounded by Cu atoms on 15 equipoint positions with occupancies varying between 0. 15(1) and 0. 97(1).
- Moeller,Jeitschko
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- Phosphorus-Rich Metal Phosphides: Direct and Tin Flux-Assisted Synthesis and Evaluation as Hydrogen Evolution Electrocatalysts
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Metal phosphides from the 3d period exhibit a range of structures and compositions. Many metal-rich phosphides and monophosphides function as heterogeneous electrocatalysts in the hydrogen evolution reaction. This paper describes the direct and tin flux-assisted synthesis of phosphorus-rich metal phosphides with MP2 or MP3 compositions. The facile synthesis of FeP2, CoP3, NiP2, and CuP2 is thermochemically driven by PCl3 formation from reactions of anhydrous metal halides and P4 vapor at 500 °C. Well-crystallized micrometer-sized particles result from these solvent-free reactions. A tin flux leads to more complete reactions at lower temperature for FeP2 and enables synthesis of a monoclinic polymorph of NiP2 rather than the kinetic cubic product formed by direct reaction. These crystalline metal phosphides are investigated as electrocatalyts for hydrogen evolution in acidic and buffered aqueous solutions. All phosphorus-rich products show very good stability in strongly acidic media. The catalytic activity for hydrogen evolution ordered by higher current at a fixed electrode geometric area and low onset potential is CoP3 > NiP2 (cubic and monoclinic) > FeP2CuP2. At high applied potentials, CuP2 undergoes surface reactions and roughening that improve its electrocatalytic activity. Correlations of the observed electrocatalytic activity with electrochemically active surface area, particle size, metallic versus semiconducting properties, and local metal coordination environment are noted for these phosphorus-rich 3d metal phosphides.
- Coleman, Nathaniel,Lovander, Matthew D.,Leddy, Johna,Gillan, Edward G.
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- Quantifying the reaction mechanisms of a high-capacity CuP2/C composite anode for potassium ion batteries
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Introducing metals into phosphorus to form metal phosphide materials as anodes for potassium ion batteries (PIBs) is an effective strategy to improve the electronic conductivity and alleviate the volume change during cycling, although with a compromise of capacity. Herein, we explore a CuP2/C composite as a novel anode for PIBs, which delivers a high reversible capacity of >450 mA h g?1. Unexpectedly, our results reveal that the POxcomponents existing in the prepared composite are reversible, through a quantitative analysisviahigh-resolution solid-state31P NMR and synchrotron X-ray diffraction tests. Their potassiation products K3PO4and K4P2O7can react with K-P alloys and turn back to POxduring depotassiation, which probably accounts for the high capacity of the prepared material. The results also illustrate a crystallization-amorphization evolution process during cycling involving nanocrystalline α-K4P6, K4P3and KP, and amorphous K4P6, KP and K3P phases, among which, the amorphous phases are identified for the first time.
- Zhao, Chen,Chen, Huixin,Liu, Haodong,Yin, Liang,Zhang, Qiaobao,Yu, Sicen,Liu, Ping,Zhong, Guiming,Lu, Can-Zhong,Yang, Yong
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- Thorium copper phosphides: More diverse metal-phosphorus and phosphorus-phosphorus interactions than U analogues
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To explore the chemical analogy between thorium and heavier actinides in soft anionic environments, three new thorium phosphides (ThCuP2, β-ThCu2P2, and ThCu5P3) have been prepared through solid-state reactions using CuI as a reaction promoter. The structure of ThCuP2 can be described as a filled UTe2-type with both dimeric P24- and monomeric P3- anions, in which Th is coordinated by eight P atoms in a bicapped trigonal prismatic arrangement and Cu is tetrahedrally coordinated by four P atoms. β-ThCu2P2 contains only P3- anions and is isostructural with BaCu2S2. In this structure, Th is coordinated by seven P atoms in monocapped trigonal prismatic geometry and Cu is tetrahedrally coordinated by four P atoms. ThCu5P3 adopts the YCo5P3-type structure consisting of P3- anions. This structure contains Th atoms coordinated by six P atoms in a trigonal prismatic arrangement and Cu atoms that are either tetrahedrally coordinated by four P atoms or square pyramidally coordinated by five P atoms. Electric resistivity measurements and electronic structure calculations on β-ThCu2P2 indicate a metal. These new compounds may be charge-balanced and formulated as Th4+Cu+(P24-)1/2P3-, Th4+(Cu+)2(P3-)2, and Th4+(Cu+)5(P3-)3, respectively. The structural, bonding, and property relationships between these Th compounds and related actinide and rare-earth phases are discussed. Titled compounds display more diverse ion-ion interactions and different electronic structures from those in UCuP2 and UCu2P2 that were synthesized under similar experimental conditions, suggesting divergence of thorium-phosphide chemistry from uranium-phosphide chemistry.
- Jin, Geng Bang,Malliakas, Christos D.,Lin, Jian
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