- Morphology control of nickel oxalate by soft chemistry and conversion to nickel oxide for application in photocatalysis
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The present work provides an effective methodology for controlled room-temperature aqueous synthesis of nickel oxalate (NiOX) nanosheets and nanoflakes in the presence of anion rich self-assembled bilayers of catanionic surfactant comprising of anionic sodium dodecyl sulfate (SDS) and cationic cetyltrimethylammonium bromide (CTAB). Encouragingly alteration of the CTAB/SDS ratio played an extraordinary role to form nanoflakes and nanosheets of NiOX. Our synthetic approach is combined with calcination to produce antiferromagnetic spherical and hexagonal nickel oxide (NiO) nanoparticles (NPs) as the end product. Synthesized nanostructured NiOX and NiO were characterized by X-ray diffraction study (XRD), energy dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). TEM studies illustrated that spherical NiO NPs have an average size around 5-10 nm and that of hexagonal NiO NPs have average width of about 22-27 nm. Temperature and field dependent magnetic properties of spherical and hexagonal NiO nanomaterials (NMs) were measured by using a SQUID magnetometer which revealed canted antiferromagnetic and spin glass nature, respectively. In addition, we report photocatalytic activity of NiO NMs, investigated on the photodegradation of phenol under ambient conditions, and as expected, the NiO having largest surface area showed best catalytic efficiency. This biomimetic catanionic surfactant inspired approach which require only metal ions as reactants have a definite potential towards an alternative, simple way of synthesizing metal oxide NMs.
- Rakshit, Soumyadipta,Chall, Sayantani,Mati, Soumya Sundar,Roychowdhury, Anirban,Moulik,Bhattacharya, Subhash Chandra
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- Controlled synthesis of spin glass nickel oxide nanoparticles and evaluation of their potential antimicrobial activity: A cost effective and eco friendly approach
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Development of an easy sustainable synthetic pathway towards oxide nanomaterials (NMs) is a necessary challenge for nanotechnology research workers. Additionally, antimicrobial activity of oxide nanoparticles against multi drug resistance pathogenic bacteria motivates scientists to focus their research on oxide materials. We report here a cost effective, simple and eco-friendly pathway of synthesizing NiO nanoparticles (NPs). X-ray diffraction and energy dispersive X-ray study confirmed their crystallinity and composition. Field emission scanning electron microscope (FESEM) was employed to understand their surface architecture and the dimension of synthesized NiO NPs were found to be 20-30 nm from transmission electron microscope (TEM) study. The as synthesized NiO demonstrated typical spin glass behaviour which is one advantage of our synthetic procedure. Antimicrobial properties of NiO NPs were investigated using Gram negative and Gram positive bacteria and their bactericidal effects were determined from minimum inhibitory concentrations (MIC) and Minimum bactericidal concentrations (MBC). Haemolytic activity revealed the nontoxic nature of the NPs towards the blood proteins at MBC. TEM images of bacteria cells treated with NiO NPs showed irreversible damages to the cell wall leading to cell death. In light of our findings a possible mechanism of the antimicrobial effect of NiO NPs has been proposed.
- Rakshit, Soumyadipta,Ghosh, Srabanti,Chall, Sayantani,Mati, Soumya Sundar,Moulik,Bhattacharya, Subhash Chandra
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- The kinetics of formation of the nickel monooxalate complex in solution
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The rate of formation of the monooxalate complex of nicklel(II) both in neutral and in acid solution has been studied by the use of a flow technique. The results are interpreted in terms of the reactions Ni2+ + A2- ?k1dk1f NiA and Ni2+ + HA- ?k2dk2f NiA + H+ where A2- represents the oxalate ion. At 25.0° and ionic strength 0.10 M, k1f = 7.5 × 104 M-1 sec.-1, k2f = 5 × 103 M-1 sec.-1, k1d = 3.6 sec.-1, and k2d = 1.5 × 103 M-1 sec.-1. Studies at various temperatures between 5 and 35° give ΔH1f* = 14 kcal, mole-1, ΔH-2f* = 14 kcal, mole-1, ΔS1f* = 12 cal. deg.-1 mole-1, and ΔS2f* = 7 cal. deg. mole-1. The results are consistent with a model in which the rate-determining step is the elimination of a water molecule from the inner hydration shell of the nickel ion.
- Nancollas,Sutin
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- Double complex salts of Pt and Pd ammines with Zn and Ni oxalates - promising precursors of nanosized alloys
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Double complex salts [M(NH3)4][M′(Ox)2(H2O)2] · 2H2O (M = Pd, Pt, M′ = Ni, Zn) were synthesized by combination of solutions containing corresponding cations [M(NH3)4]2+ and anions [M′(Ox)2(H2O)2]2-. The salts obtained were characterized by IR spectroscopy, thermal analysis, powder and single crystal X-ray diffraction. The prepared compounds are isostructural and crystallize in the orthorhombic crystal system (space group I222, Z = 2). Thermal decomposition of the salts in helium or hydrogen atmosphere at 200-400 °C results in formation of nano-sized bimetallic powders. Depending on the phase diagram of the respective bimetallic system and temperature conditions, they can be single phase or multiphase products. In particular, thermal decomposition of double complex salts [M(NH3)4][Zn(Ox)2(H2O)2] · 2H2O (M = Pd, Pt) results in formation of PdZn and PtZn intermetallic compounds, correspondingly. Decomposition of [Pd(NH3)4][Ni(Ox)2(H2O)2] · 2H2O affords a disordered solid solution Pd0.5Ni0.5. Disordered Pt0.5Ni0.5 was obtained from [Pt(NH3)4][Ni(Ox)2(H2O)2] · 2H2O in helium atmosphere, while in hydrogen atmosphere - a two-phase mixture of disordered Pt0.5Ni0.5 and ordered PtNi. In all cases crystallite sizes of bimetallic particles varied within 50-250 A?.
- Zadesenets,Filatov,Yusenko,Shubin,Korenev,Baidina
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- Diamine incorporated compounds derived from polymeric nickel(II) fumarates and oxalates: Crystal structure, spectral and thermal properties of [Ni(en)3](O2C{single bond}CH{double bond, long}CH{single bond}CO2)·3H2O and [Ni(en)3](O2C{single bond}CO2)
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Lewis-base mediated fragmentation of polymeric nickel(II) fumarate and oxalate are attempted using chelating σ-donor diamines like ethylenediamine (en) and 1,3-diaminopropane (dap) in various conditions which yielded [Ni(en)3](fum)·3H2O (1), [Ni(en)3](ox) (2), [Ni(dap)2(fum)] (3) and [Ni(dap)(ox)]·2H2O (4). While 1 and 2 are molecular products each containing octahedral [Ni(en)3]2+ moieties and the anionic dicarboxylate species, 3 and 4 are dap-incorporated polymeric products. The fumarate derivative 1 containing [Ni(en)3]2+ moieties crystallizes in the monoclinic space group C2/c with a = 17.899(4) A?, b = 11.747(2) A?, c = 10.748(2) A?, β = 125.59(3)°, V = 1837.7(6) A?3, Z = 4, while the oxalate analogue 2 is seen to be in the trigonal space group P-31c with a = 8.8770(13) A?, b = 8.8770(13) A?, c = 10.482(2) A?, γ = 120°, V = 715.3(2) A?3, Z = 2. The octahedral [Ni(en)3] units in both 1 and 2 are seen to be strongly H-bonded to the dicarboxylate moieties through the coordinated en units leading to a three-dimensional network. However, in 1 the water molecules also take part in the H-bonding and contribute to the overall 3D structure. In both 1 and 2 the crystal packing is done with the [Ni(en)3]2+ units with absolute configuration Λ(δδδ) and its mirror conformer with Δ configuration in exactly equal numbers. Spectral (IR and UV-Visible) and magnetic measurements were carried out and some of the ligand-field parameters like Dq, B and β were evaluated for all the four compounds. These values suggest the presence of octahedrally coordinated nickel(II) in all the four complexes. Spectral data suggest that 3 has the two chelating dap moieties and the fumarate coordinated in η1 form through both its carboxylate moieties while 4 has one chelating dap and the oxalate moiety coordinated in η4-bis-chelating form. Though both 1 and 2 are made of the same type of [Ni(en)3]2+ units their thermograms give entirely different thermal features; 1 showing three clearly successive and step-wise dissociation of each en unit while 2 having a combined loss of two en units in the first thermal step. The relevant thermodynamic and kinetic parameters like Ea and ΔS also could be evaluated for various thermal steps for the compounds 1-4 using Coats-Redfern equation.
- Padmanabhan,Joseph, James C.,Huang, Xiaoying,Li, Jing
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- Nickel(II) complexes with 2-hydroxyethyliminodioacetic acid in aqueous solutions of dicarboxylic acids
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The equilibria in binary and ternary systems containing a nickel(II) salt, 2-hydroxyethyliminodi-acetic acid, and dicarboxylates were studied by spectrophotometric and potentiometric methods with NaClO4 as the supporting electrolyte at I = 0.1 and T = 20 ± 2°C. The molar and protic composition and the pH regions of existence of the complexes were determined, the stability constants of complexes containing the same or different ligands were determined. The fractional distribution of the complexes as the function of acidity was elucidated. The experimental data were treated using mathematical models to estimate the possibility of existence of a broad range of complex species in solution and to distinguish the species that are sufficient to take into account for reproducing the experimental results.
- Kornev,Semenova
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- P-Type dye-sensitized solar cell based on nickel oxide photocathode with or without Li doping
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Nickel oxide (NiO) nanostructures are synthesized using a microwave-assisted hydrothermal method. The hydrothermal bath has a solution of nickel salt mixed with precipitating agent. During the synthesis the microwave temperature, the concentration of nickel salt and precipitating agent along with the pH of the reaction solutions are changed and different morphologies of nickel oxide are obtained. The resulting nickel oxide nanostructures are characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer-Emmett-Teller method and X-ray photoelectron spectroscopy. Thus formed NiO has been used as a photocathode in dye-sensitized solar cell. Lithium doped NiO showed better IPCE as well as solar to electrical conversion efficiency than the undoped NiO.
- Wang, Hui-Tzu,Mishra,Chen, Peter,Ting, Jyh-Ming
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- Rapid mass production of iron nickel oxalate nanorods for efficient oxygen evolution reaction catalysis
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The NiFe layered-double-hydroxide (NiFe-LDH) and the NiFe metal-organic framework (NiFe-MOF) demonstrate the best catalytic activity among NiFe-based materials for the oxygen evolution reaction (OER), which is important for efficient hydrogen production. However, the preparation processes of these materials are usually cumbersome and have a low yield, which eliminates their most critical advantage of being low cost. We propose a method for rapidly and efficiently preparing porous (Ni0.5Fe0.5)C2O4nanorods with an excellent OER catalytic performance. The overpotential of (Ni0.5Fe0.5)C2O4is 266 mV at 20 mA cm?2under alkaline conditions, and the Tafel slope is 54.39 mV dec?1. Furthermore, analysis of the changes in the surface properties of the material before and after catalysis determined that the real active material is (Ni0.5Fe0.5)(OH)x(C2O4)1?x. Using a simple scaled-up experiment, (Ni0.5Fe0.5)C2O4is mass-produced (40 g)viadirect synthesis in 5 min. The composition and performance of the mass-produced sample are analysed under the same conditions, and (Ni0.5Fe0.5)C2O4still has a good catalytic performance and its composition has not changed. The efficient synthesis of (Ni0.5Fe0.5)C2O4nanorods with a porous structure provides a new option for the development of commercial catalysts using non-precious metals.
- Hu, Huixia,Lei, Xiang,Li, Shumei,Peng, Ruzhen,Wang, Jinliang
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p. 328 - 333
(2021/12/31)
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- Very fast crystallisation of MFe2O4 spinel ferrites (M = Co, Mn, Ni, Zn) under low temperature hydrothermal conditions: A time-resolved structural investigation
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MFe2O4 spinel ferrites (M = Co, Mn, Ni, Zn) were synthesised through a low-temperature aqueous route combining co-precipitation of oxalates and hydrothermal treatment at 135 °C. With the objective of gaining a deeper understanding of the structural evolution of the compounds to crystalline materials during the synthetic process, samples were prepared within different reaction times, showing in most cases a fully crystalline habit already after short treatment times. The resulting solids were characterised through several state-of-the-art analytical techniques, both on the atomic (XAS) and mesoscopic (XRPD, SAXS) scales. In parallel, temperature-programmed characterisation was carried out to investigate the evolution of the compounds during the heating process.
- Dolcet, Paolo,Diodati, Stefano,Zorzi, Federico,Voepel, Pascal,Seitz, Christoph,Smarsly, Bernd M.,Mascotto, Simone,Nestola, Fabrizio,Gross, Silvia
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p. 2257 - 2268
(2018/05/29)
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- Improved high rate performance and cycle stability for LiNi0.8Co0.2O2 by doping of the high valence state ion Nb5+ into Li+ sites
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High rate performance has been a challenging issue for LiNi0.8Co0.2O2 material. Elemental doping is a very effective method that has been used to maintain the structure of cathode materials with high stability and improve the high rate performance. Encouraged by previous research and considering the shortcomings of LiNi0.8Co0.2O2, materials with a composition of Li1-xNbxNi0.8Co0.2O2 (x = 0, 0.01, 0.03) were prepared by co-precipitation and the solid phase sintering method. The structure and electrochemical performance were studied in detail. The results from structural analysis suggested that the doping element was successfully doped into LiNi0.8Co0.2O2. Electrochemical measurements suggested that high rate capacities led to distinct improvements for a moderate Nb-doping content. Specifically, the initial capacities delivered by LiNi0.8Co0.2O2 and Li0.99Nb0.01Ni0.8Co0.2O2 increased from 97 to 156 mAh/g at 25 °C and 62.1 to 144.7 mAh/g at 50 °C at a rate of 5 C. In addition, the results from differential scanning calorimetry (DSC) and thermogravimetric (TG) analysis demonstrated that the Nb-doped LiNi0.8Co02O2 had a higher thermal stability in the charged state compared to the un-doped material. Therefore, the Li+ sites in LiNi0.8Co0.2O2 were partially substituted by the high valence element Nb, which can lower Li/Ni mixing and polarization, accelerate the migration rate of Li+ and stabilize the structure of the cathode material, thus improving the high rate performance and cycling stability.
- Wu, Kang,Jia, Guofeng,Shangguan, Xuehui,Yang, Guowei,Zhu, Zenghu,Peng, Zhengjun,Zhuge, Qin,Li, Faqiang,Cui, Xiaoling
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p. 700 - 709
(2018/07/06)
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- Chalcogenide and pnictide nanocrystals from the silylative deoxygenation of metal oxides
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Transition metal chalcogenide and pnictide nanocrystals are of interest for optoelectronic and catalytic applications. Here, we present a generalized route to the synthesis of these materials from the silylative deoxygenation of metal oxides with trimethylsilyl reagents. Specific nanophases produced in this way include Ni3S2, Ni5Se5, Ni2P, Co9S8, Co3Se4, CoP, Co2P, and heterobimetallic (Ni/Co)9S8. The resulting chalcogenide nanocrystals are hollow, likely due to differential rates of ion diffusion during the interfacial phase transformation reaction (Kirkendall-type effect). In contrast, the phosphide nanocrystals are solid, likely because they form at higher reaction temperatures. In all cases, simultaneous partial decomposition of the deoxygenating silyl reagent produces a coating of amorphous silica around the newly formed nanocrystals, which could impact their stability and recyclability.
- Lin, Chia-Cheng,Tan, Shannon J.,Vela, Javier
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p. 20351 - 20358
(2017/10/13)
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- Mimicking mineral neogenesis for the clean synthesis of metal-organic materials from mineral feedstocks: Coordination polymers, MOFs and metal oxide separation
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We present a systematic study of a mild approach for the activation of metal oxides, involving reactivity and self-assembly in the solid state, which enables their solvent-free chemical separation and direct solvent-free and low-energy conversion into coordination polymers and open metal-organic frameworks (MOFs). The approach is inspired by geological biomineralization processes known as mineral weathering, in which long-term exposure of oxide or sulfide minerals to molecules of biological origin leads to their conversion into simple coordination polymers. This proof-of-principle study shows how mineral neogenesis can be mimicked in the laboratory to provide coordination polymers directly from metal oxides without a significant input of either thermal or mechanical energy, or solvents. We show that such "aging" is accelerated by increased humidity, a mild temperature increase and/or brief mechanical activation, enabling the transformation of a variety of high-melting (800 °C-2800 °C) transition (MnII, CoII, Ni II, CuII, and Zn) and main group (Mg and PbII) oxides at or near room temperature. Accelerated aging reactions are readily scaled to at least 10 grams and can be templated for the synthesis of two-dimensional and three-dimensional anionic frameworks of Zn, Ni(ii) and Co(ii). Finally, we demonstrate how this biomineralization-inspired approach provides an unprecedented opportunity for solvent-free chemical segregation of base metals, such as Cu, Zn and Pb, in their oxide form under mild conditions.
- Qi, Feng,Stein, Robin S.,Friscic, Tomislav
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supporting information
p. 121 - 132
(2014/01/06)
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- Catalytic ozonation of 2-ethoxy ethyl acetate using mesoporous nickel oxalates
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In this communication, synthesis of mesoporous nickel oxalate and its catalytic activity in ozonation of 2-ethoxy ethyl acetate (2-EEA) was reported. The mesoporous nickel oxalate was synthesized by simple method without using any template. The XRD and HR
- Amutha,Sillanp??, Mika,Lee, Gang-Juan,Lin, Jir-Chi,Yang, Chuan-Kai,Wu, Jerry J.
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- Synthesis and thermal decomposition of mixed 2,4′-bipyridine-oxalato complexes with Mn(II), Co(II), Ni(II) and Cu(II)
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The mixed 2,4′-bipyridine-oxalato complexes of the formulae M(2,4′-bipy)2C2O4·2H2O (M(II) = Mn, Co, Ni, Cu; 2,4′-bipyridine = 2,4′-bipy or L; C2O42 = ox) have been prepared and c
- Czakis-Sulikowska,Radwanska-Doczekalska,Markiewicz
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p. 145 - 151
(2008/10/08)
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- Synthesis and thermal decomposition of [Ni2(C4H4O6)2]·7H2O
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The paper describes the synthesis, characterization and thermal decomposition of nickel(II) bis(tartrato) nickelate(II) heptahydrate [Ni2(C4H4O6)2]·7H2O. The complex was characterized by elemental analysis, magnetic moment measurement, infrared. ESR and electronic spectroscopy. The experimental evidences indicate that complex is likely to have metal bonding. The thermal decomposition of the complex produced NiO in air at about 360°C and in nitrogen at about 380°C as the final product. Some of the intermediates produced during the thermoanalysis were isolated by temperature arrest technique and identified by analytical and spectroscopic methods. A tentative reaction mechanism is proposed for the thermal decomposition of the complex in air and nitrogen.
- Dass,Sarmah
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p. 137 - 145
(2008/10/09)
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- Temperature programmed reduction studies of nickel manganite spinels
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Temperature programmed reduction (TPR) of manganese, nickel monometallic oxides (Mn3O4, Mn2O3, MnO2 and NiO) and nickel manganite oxides (spinels NixMn3 - xO4 with 0 3), under hydrogen, was investigated. Final and transient products produced were characterised by XRD. Manganese oxides are successively reduced to less oxidised oxide (MnO2 gives Mn2O3 which gives Mn3O4 which further gives MnO). Although the position and shape of the peaks corresponding to the different reduction steps depend on experimental conditions and sample granulometry, activation energy is found to be the same for the same kind of transformation. Whatever is the crystalline structure, nickel manganites are reduced in two main steps. During the first step, formation of a solid solution of NiO in MnO matrix arises then reduction of Ni2+ cations occur during the last step and the final product of reaction is a mixture of MnO and metallic nickel. Hence, contrary to manganese oxides, Mn cations of mixed compounds undergo direct reduction to Mn2+, giving MnO without any other way through less oxidised species of manganese. We think that it should be explained by the promoting effect of nickel.
- Christel, Laberty,Pierre, Alphonse,Abel, Duprat Anne-Marie Rousset
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- Thermal decomposition of energetic materials. 34. Decarbonylation, decarboxylation, and coupling reactions of metal propiolates, M[O2CC≡CH]
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The thermal decomposition of metal propiolate salts, M[O2CC≡CH]x·y[HO 2CC≡CH]·zH2O, where M = Na (x = 1, y = 0, z = 0), K (x = 1, y = 0, z = 0), Rb (x = 1, y = 0.5, z = 0), Co (x = 2, y = 0, z = 3), Ni (x = 2, y = 0, z = 0), and Zn (x = 2, y = 0, z = 2), is described for slow heating by TGA, DSC, and IR spectroscopy and for fast heating (80-300°C/s) by FTIR/temperature profiling. The decomposition temperatures and ΔHdec of the Na+, K+, and Rb+ salts predict their tendency to thermalize by decarbonylation, decarboxylation, or coupling when in the unconfined state. Decarbonylation yields M2CO3, CO, C, and C2H2, while decarboxylation yields M2CO3, CO2, C, and C2H2. Coupling leads to a solid product resembling an acetylenedicarboxylate salt. The CO/CO2 and C2H2/COx gas product ratios for these salts support these descriptions. A lower decomposition temperature, lower lattice energy, and smaller ΔH of decomposition favors decarboxylation and coupled products (Rb+), while the reverse favors decarbonylation (Na+, K+). Extensions of these notions to the Co2+, Ni2+, and Zn2+ salts indicate that the decomposition temperature reliably predicts their tendency to decarbonylate and form a carbonate (Ni2+), or decarboxylate and form coupled products (Co2+, Zn2+). All six salts give evidence of coupling when slowly thermalized between two BaF2 plates.
- Stoner Jr.,Brill
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p. 4500 - 4506
(2008/10/08)
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- CRYSTAL STRUCTURE OF THE ORDERED PHASE OF ZINC OXALATE AND THE STRUCTURE OF ANHYDROUS Fe2+, Co2+, Ni2+, Cu2+, AND Zn2+ OXALATES
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Conditions were found for the preparation of ordered phases of Fe2+, Co2+, Ni2+, and Zn2+ oxalates.The powder pattern was used to determine the structure of the ZnC2O4 phase using 62 reflections obtained with λCu Kα radiation and refinement by the full-matrix method of least squares to R = 0.12 (space group P21/n, Z = 2).This structure consist of cation-anion chains connected by Zn-O bonds in a three-dimensional framework.The zinc ion has octahedral coordination and the oxygen atoms differ in the number of their bonds with the cation, leading to inequality in the C-O bond lengths in the C2O42- anion (1.40 and 1.15 Angstroem).The unit cell parameters were found and refined for all the ordered phases.Indexing was carried out for the powder patterns of the disordered isostructural CuC2O4 phases with superpositional structure.
- Kondrashev, Yu. D.,Bogdanov, V. S.,Golubev, S. N.,Pron', G. F.
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