Synthesis and characterization of niobium doped hexagonal tungsten bronze in the systems, CsxNbyW1−yO3

Dey, Kalpana R.; Debnath, Tapas; Rüscher, Claus H.; Sundberg, Margareta; Hussain, Altaf

doi:10.1007/s10853-010-4932-3

Cited by 14 publications

(11 citation statements)

References 19 publications

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“…Therefore, the increased phonon absorption intensity for y ≥ 0.10 indicates a significant decrease in the free carrier contribution and results nonmetallic nature of the compounds. The spectra observed for the sample K 0.30 Ta y W 1-y O 3 are in good agreement with powder related spectra reported by Dey et al 15 recently.…”

Section: Resultssupporting

confidence: 91%

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Study of Tantalum Substituted Potassium Tungsten Bronzes

Shakil

Debnath

Rüscher

et al. 2012

J. Bangla. Chem. Soc.

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A series of compounds K x Ta y W 1-y O 3 with x = 0.30, 0.00 ≤ y ≤ 0.30 and x = 0.55, 0.00 ≤ y ≤ 0.10 were synthesized by conventional solid-state method. The samples were characterized using XRD and FTIR spectroscopy. X-ray powder patterns reveal that the samples with compositions x = 0.30, y ≤ 0.30 show hexagonal tungsten bronze (HTB) type phase and the samples with x = 0.55, 0.02 ≤ y ≤ 0.10 show a mixture of two phases (K-HTB and tetragonal potassium tungsten bronze, K-TTB). The samples of the system, K 0.30 Ta y W 1-y O 3 with 0.00 ≤ y ≤ 0.15 shows no significant change in the cell parameters. However, for the composition y > 0.15, the cell parameter a decreases and c increases with increasing Ta content, which may be explained by the ordering of Ta for y > 0.15 suggesting the transformation to another space group. The appearance of absorption peak in the infrared absorption spectra of K 0.3 Ta y W 1-y O 3, y > 0.10 samples indicate the transition to non-metallic phase.

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Section: Resultssupporting

confidence: 91%

“…when x > y) or fully substituted (i.e. when x = y) by other ions [12][13][14][15][16][17][18] . Fully substituted phase analogue to ITB is called bronzoid 19 .…”

Section: Introductionmentioning

confidence: 99%

Study of Tantalum Substituted Potassium Tungsten Bronzes

Shakil

Debnath

Rüscher

et al. 2012

J. Bangla. Chem. Soc.

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“…A similar displacement has been reported in Nb-doped hexagonal WO3 samples, related to the expansion of d001 spacing when increasing the Nb/W ratio 38 and in the HTB-type systems Cs0.25NbyW1-yO3 and Cs0.3NbyW1-yO3 (0.0 ≤ y ≤ 0.25 and 0.0 ≤ y ≤ 0.3, respectively). 24 New diffraction maxima appear at 960ºC, their intensity increasing at 975ºC. At this temperature, the furnace was held isothermally and in situ diffraction patterns were then acquired at different times.…”

Section: Methodsmentioning

confidence: 99%

Self-Organized Transformation from Hexagonal to Orthorhombic Bronze of Cs–Nb–W–O Mixed Oxides Prepared Hydrothermally

Soriano

García-González

Concepción

et al. 2017

Crystal Growth & Design

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The thermal transformation of hydrothermally prepared Cs-Nb-W-O mixed oxides has been studied in the 25-1000º C temperature range. Structural evolution of the prepared solids was monitored by in-situ synchrotron X-ray diffraction (XRD), absorption spectroscopy (XAS) techniques and conventional powder X-ray diffraction and studied by thermogravimetric analysis, infrared (FTIR) and Raman spectroscopy and high resolution transmission electron microscopy (HRTEM and STEM). The as-grown solids show the hexagonal tungsten bronze (HTB) structure, which can be stabilized above 900 ºC depending on the chemical composition. From this temperature, solids are selectively transformed into the orthorhombic Cs0.5(Nb2.5W2.5)O14 structure-type. The same results are obtained for Cs0.5(Nb2.5W2.5-xMx)O3, with M= V or Mo; (x= 0-1.25). A mechanism for the quantitative transformation at high temperature is proposed in terms of the relative occupancy of the hexagonal channels in the HTB-type phase as well as the Nb/(W+V) ratio.

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“…The concentration and dynamics of the alkali metal cations in the WO 3 host structure significantly tailor the physical properties, such as tuning superconductivity [8,9]. Substitutions of W 6þ with SOJT susceptible pentavalent (M 5 þ ) Nb and Ta in the A x M 5 þ y W 5 þ xÀ y W 6þ 1À y O 3 bronzes are also known [10,11], where the M 5 þ cation sits in the centroid of the MO 6 octahedron. When x¼y, the compound is fully oxidized and known as bronzoid [1].…”

Section: Introductionmentioning

confidence: 99%

Nanoscale building blocks in a novel lithium arsenotungsten bronze: Synthesis and characterization

Zhao

Murshed

Huq

et al. 2015

Journal of Solid State Chemistry

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a b s t r a c tWe report on a novel compound Li 3 AsW 7 O 25 obtained by solid-state reaction and characterized by diffraction and spectroscopic methods. The bronze-type compound crystallizes in the orthorhombic space group Pbca with a¼ 724.38(3) pm, b ¼1008.15(4) pm, c ¼ 4906.16(17) pm and Z¼8. The structure is built up by chains of WO 6 octahedra interconnected by AsO 4 tetrahedra and WO 6 octahedra forming a polyhedral arrangement as seen in intergrowth tungsten bronzes. The X-ray single crystal structure refinement allows solving the complex arsenotungstate framework. The powder neutron diffraction data analysis locates the lithium atoms. Thermal analysis showed that Li 3 AsW 7 O 25 is stable up to its melting at 1135(3) K followed by a decomposition at 1182(5) K. The Kubelka-Munk treatment of the UV-vis spectrum revealed a wide band gap in the range of 2.84-3.40 eV depending on the presumed electron transition type.

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Synthesis and characterization of niobium doped hexagonal tungsten bronze in the systems, CsxNbyW1−yO3

Cited by 14 publications

References 19 publications

Study of Tantalum Substituted Potassium Tungsten Bronzes

Study of Tantalum Substituted Potassium Tungsten Bronzes

Self-Organized Transformation from Hexagonal to Orthorhombic Bronze of Cs–Nb–W–O Mixed Oxides Prepared Hydrothermally

Nanoscale building blocks in a novel lithium arsenotungsten bronze: Synthesis and characterization

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