| 1. |
- Flemström, A., et al.
(författare)
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Effects from hydrogen bonds on water structure in (H3O)2[Mo6Cl8X6]·yH2O X=Cl (y=7), Br (y=6), or I (y=6)
- 2002
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Ingår i: Solid State Sciences. - 1293-2558 .- 1873-3085. ; 4:8, s. 1017-1022
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Tidskriftsartikel (refereegranskat)abstract
- The compounds (a) (H3O)2[Mo6Cl8Cl6]·7H2O, (b) (H3O)2[Mo6Cl8Br6]·6H2O and (c) (H3O)2[Mo6Cl8I6]·6H2O were synthesized from MoCl2 and the corresponding halide acid. The structures were determined by X-ray diffraction and refined in the monoclinic space groups, (a) C2/c and for (b) and (c) P21/a. The cell parameters were for (a), a=17.3607(2), b=9.1351(7), c=18.6300(2) Å and β=98.13(1)°, (b) a=17.4295(2), b=9.3803(10), c=9.3769(12) Å and β=101.04(1)° and (c) a=18.0083(10), b=9.7612(10), c=9.8139(12) Å and β=100.20(2)°. The positions of the hydrogen atoms were determined by theoretical energy optimization. The structures are compared with respect to the effect of hydrogen bonding on the water structure.
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| 2. |
- Hannerz, H, et al.
(författare)
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Structure and magnetic susceptibility of MnNb3O6
- 1999
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Ingår i: Solid State Sciences. - 1293-2558 .- 1873-3085. ; 1, s. 567-575
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Tidskriftsartikel (refereegranskat)abstract
- The mixed valence state niobium compound MnNb3O6 was found while studying phase formations in the system MnO-Nb2O5-NbO. It is isostructural with AxNb3O6, x ≤ 1 and A = Na, Ca. Single crystals were obtained by heating MnC2O4 · 2H2O and Nb2O5 in a flow of H2 at 1300 °C. Monophasic samples were also prepared by heating stoichiometric mixtures of MnO, Nb2O5 and Nb in niobium ampoules under Ar(g) at 1100 °C. The crystal structure of MnNb3O6 (Immm, Z = 4, a = 7.1057(5), b = 10.1420(6), c = 6.5341(5) Å) was refined, using singlecrystal MoKα X-ray diffraction data, to a weighted R value of 0.018 for 329 unique reflections. The structure contains undulating layers of NbO6 octahedra of the type α2[NbO6/2]in the ac-plane, with the octahedra sharing edges along [001]and corners along [100]. Between the layers there are columns along [001]of edge-sharing square MnO8 prisms alternating with columns containing Nb2O8 clusters with an Nb-Nb distance of 2.6163(5) Å. The magnetic susceptibility shows a Curie-Weiss behaviour: χM = C/(T+θ) with θ ≈ −22 K and μeff = 6.0(1) μB for T ≥ ca. 35 K, with a small deviation from this dependence at lower temperatures, indicating Mn2+ ions with localised magnetic moments and antiferromagnetic interactions.
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| 3. |
- Istomin, S. Ya., et al.
(författare)
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A neutron powder diffraction study of Na1-xSrxTaO3 (x=0.2 and 0.3)
- 2002
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Ingår i: Solid State Sciences. - 1293-2558 .- 1873-3085. ; 4:2, s. 191-195
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Tidskriftsartikel (refereegranskat)abstract
- Black powder samples of the reduced oxotantalates Na1-xSrxTaO3 x = 0.2 and 0.3 were prepared via solid state reactions from appropriate amounts of NaTaO3, Sr5Ta4O15 and Ta (99.99%) in sealed tantalum ampoules at 1500degreesC. They crystallize in variants of the perovskite type structure (a(per)). According to structural refinements from neutron powder diffraction data Na0.8Sr0.2Ta03 crystallizes orthorhombic in the GdFeO3 type structure with unit cell parameters a approximate to root2 x a(per), b approximate to 2 x a(per), c approximate to root2 x a(per) and space group Prima. The structure of the more reduced phase Na0.7Sr0.3TaO3 is tetragonal with unit cell parameters a approximate to root2 x a(per), c approximate to 2 x a(per) and space group P4/mbm.
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| 4. |
- Johansson, Börje, et al.
(författare)
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Chemical composition-elastic property maps of austenitic stainless steels
- 2003
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Ingår i: Solid State Sciences. - 1293-2558 .- 1873-3085. ; 5:6, s. 931-936
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Tidskriftsartikel (refereegranskat)abstract
- Despite a tremendous development during the last decades, both as regards computer power and methodology, it has remained impossible to treat steel at a fundamental atomic level. However, recently we have shown [L. Vitos, P.A. Korzhavyi, B. Johansson, Phys. Rev. Lett. 88 (2002) 155501] that the most efficient theories of random substitutional alloys combined with advanced numerical techniques have made possible to establish a theoretical insight to the electronic structure of stainless steels. Here a detailed description of the quantum-mechanical modeling of austenitic stainless steels is presented. We adopt an ab initio electronic structure calculation method based on the coherent potential approximation, implemented within the framework of the exact muffin tin orbitals theory, to map the chemical composition distributions of austenitic stainless steels into the elastic property distributions. The so generated database can be fruitfully used in the design of new class of steel alloys.
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| 5. |
- Valldor, M., et al.
(författare)
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The structure of the new compound YBaCo4O7 with a magnetic feature
- 2002
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Ingår i: Solid State Sciences. - 1293-2558 .- 1873-3085. ; 4:7, s. 923-931
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Tidskriftsartikel (refereegranskat)abstract
- Single crystals and pure powder samples of the new compound YBaCo4O7 have been obtained by solid-state reactions, using different temperature programs. From X-ray powder diffraction the structure was determined as hexagonal, space group P6(3)mc. having the cell parameters a = 6.2982(4) and c = 10.2467(9) Angstrom. This phase is isostructural with that previously reported for LuBaZn3.09Al0.91O7. Refinements of powder neutron diffraction data collected at two different temperatures and X-ray single crystal data at room temperature, agree well. Changes with temperature in the relative positions of Co and its surrounding oxygen atoms are the only geometrical manifestation of a probable spin-glass transition at about 65 K from the high temperature paramagnetic state.
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| 6. |
- Zhu, Bin, et al.
(författare)
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Calcium doped ceria-based materials for cost-effective intermediate temperature solid oxide fuel cells
- 2003
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Ingår i: Solid State Sciences. - : Elsevier BV. - 1293-2558 .- 1873-3085. ; 5:8, s. 1127-1134
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Tidskriftsartikel (refereegranskat)abstract
- This paper studies preparation and characterization of the calcium doping ceria (CCO) and carbonate composite materials. The material preparation was performed based on an oxalate co-precipitation. Various material characterizations were carried on the material phase structure based on XRD, TG/DSC and their fuel cell applications. The CCO materials showed a two-phase composite with very high ionic conductivity, 0.01 to 0.5 S cm(-1) between 400 and 700degreesC. Using the CCO-composites as the electrolytes for intermediate temperature solid oxide fuel cells (ITSOFC) a high performance, e.g., 600 mW cm(-2) was demonstrated at 600degreesC.
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| 7. |
- Adam, Rania Elhadi, 1978-, et al.
(författare)
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Synthesis of Mg-doped ZnO NPs via a chemical low-temperature method and investigation of the efficient photocatalytic activity for the degradation of dyes under solar light
- 2020
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Ingår i: Solid State Sciences. - : Elsevier. - 1293-2558 .- 1873-3085. ; 99
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Tidskriftsartikel (refereegranskat)abstract
- Doped semiconductors nanostructures (NSs) have shown great interest as a potential for green and efficient photocatalysis activities. Magnesium (Mg)-doped zinc oxide (ZnO) nanoparticles (NPs) has been synthesized by a one-step chemical low temperature (60 °C) co-precipitation method without further calcination and their photocatalytic performance for photodegradation of Methylene blue (MB) dye under the illumination of solar light is investigated. The crystal structure of the synthesized NPs is examined by X-ray diffraction (XRD). XRD data indicates a slight shift towards higher 2θ angle in Mg-doped samples as compared to the pure ZnO NPs which suggest the incorporation of Mg2+ into ZnO crystal lattice. X-ray photoelectron spectroscopy (XPS), UV–Vis spectrophotometer and cathodoluminescence (CL) spectroscopy, were used to study electronics, and optical properties, respectively. The XPS analysis confirms the substitution of the Zn2+ by the Mg2+ into the ZnO crystal lattice in agreement with the XRD data. The photocatalytic activities showed a significant enhancement of the Mg-doped ZnO NPs in comparison with pure ZnO NPs. Hole/radical scavengers were used to reveal the mechanism of the photodegradation. It was found that the addition of the Mg to the ZnO lattices increases the absorption of the hydroxyl ions at the surface of the NPs and hence acts as a trap site leading to decrease the electron-hole pair and consequently enhancing the photodegradation.
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| 8. |
- Becker, Richard, et al.
(författare)
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Crystal structure and magnetic properties of the new cobalt tellurite halide Co5(TeO3)4X2 (X = Cl, Br)
- 2007
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Ingår i: Solid State Sciences. - : Elsevier BV. - 1293-2558 .- 1873-3085. ; 9:3-4, s. 223-230
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Tidskriftsartikel (refereegranskat)abstract
- Two new cobalt tellurite halides Co5(TeO3)4Cl2 and Co5(TeO3)4Br2 have been synthesized and found to be iso-structural with Ni5(TeO3)4X2 (X = Cl, Br). Co5(TeO3)4X2 crystallizes in the monoclinic system space group C2/c, and the Br-phase has the lattice parameters a = 20.440(1) Å, b = 5.2760(2) Å, c = 16.4710(7) Å, β = 124.790(5)°, and Z = 4. The crystal structures were solved from single-crystal X-ray data, R1 = 1.90 and 1.77, respectively, for the Cl- and Br-phases. The crystal structure is layered with only weak van der Waals' interactions in between the layers. The layers are built by large [Co5O16X2] groups consisting of five edge- and face-sharing Co-octahedra. Each group is connected to adjacent groups via corner sharing through common oxygen atoms as well as through [TeO3E] groups. Magnetic susceptibility measurements on oriented single crystals reveal pronounced anisotropy in a broad temperature range and clear signs of antiferromagnetic ordering at low temperatures. Anisotropic susceptibility of an iso-structural Ni-based compound was also studied and compared with the corresponding results of Co5(TeO3)4X2. Magnetic anisotropy is discussed in framework of single-ion anisotropy effects.
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| 9. |
- Beran, P., et al.
(författare)
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Neutron powder diffraction study of Ba3ZnRu2-xIrxO9 (x=0, 1, 2) with 6H-type perovskite structure
- 2015
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Ingår i: Solid State Sciences. - : Elsevier BV. - 1293-2558 .- 1873-3085. ; 50, s. 58-64
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Tidskriftsartikel (refereegranskat)abstract
- The triple perovskites Ba3ZnRu2-xIrxO9 with x = 0, 1, and 2 are insulating compounds in which Ru(Ir) cations form a dimer state. Polycrystalline samples of these materials were studied using neutron powder diffraction (NPD) at 10 and 295 K. No structural transition nor evidence of long range magnetic order was observed within the investigated temperature range. The results from structural refinements of the NPD data and its polyhedral analysis are presented, and discussed as a function of Ru/Ir content.
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| 10. |
- Cho, Kanghee, et al.
(författare)
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Mesopore generation by organosilane surfactant during LTA zeolite crystallization investigated by high-resolution SEM and Monte Carlo simulation
- 2011
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Ingår i: Solid State Sciences. - : Elsevier BV. - 1293-2558 .- 1873-3085. ; 13:4, s. 750-756
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Tidskriftsartikel (refereegranskat)abstract
- The crystallization of LTA zeolite under a hydrothermal synthesis condition that contained a quaternary ammonium-type organosilane surfactant was studied with X-ray powder diffraction (XRD), high-resolution scanning electron microscopy (HRSEM) and Monte Carlo simulation of the crystal growth. The hydrothermal reaction products were collected at various crystallization times, and investigated with XRD and HRSEM. The HRSEM images of the final zeolite products were taken as synthesized and also after cross-sectioning with an argon ion beam. The HRSEM investigation revealed presence of a disordered network of mesoporous channels that penetrated the microporous zeolite crystal. Unless the loading of the surfactant was exceedingly high, the microporous zeolite particles exhibited truncated cubic morphologies that were almost like single crystals, despite penetration by the mesopores. The outline of the zeolite particle became progressively rounded as the mesoporosity was increased according to the surfactant loading. The mesoporosity in the zeolite crystals was well maintained against crystal-ripening processes for 6 d. This result supports the fact that the organosilane surfactant micelles became incorporated inside the zeolite crystal as a mesopore generator during the crystallization process. Data from Monte Carlo simulation agreed with these experimental results.
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