Phase Transitions in Sodium Tungsten Bronzes

Ribnick, A. S.; Post, B.; Banks, Elliot

doi:10.1021/ba-1964-0039.ch023

Cited by 56 publications

(43 citation statements)

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“…One apparent exception to this rule is the homogeneity range (0.28 < x < 0.38) found for this structure in NaxWO 3 (Ribnick, Post & Banks, 1963;Magn61i, 1950b). Equilibrium preparations of NaxWO 3 have a cubic-perovskite structure above x ~.…”

Section: Resultsmentioning

confidence: 91%

The crystal structure of K_0.54(Mn,Fe)F₃ at room temperature

Banks¹,

Nakajima²,

Williams³

1979

Acta Crystallogr Sect B

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Section: Resultsmentioning

confidence: 91%

The crystal structure of K_0.54(Mn,Fe)F₃ at room temperature

Banks¹,

Nakajima²,

Williams³

1979

Acta Crystallogr Sect B

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“…The electrochemical properties of WO 3 are related to the reversible insertion/extraction of foreign ions into the cluster depending on its crystal structure. Several studies have demonstrated that the tendency of ion insertion/extraction enhances with increasing the symmetry of crystalline forms, i.e., monoclinic phase < orthorhombic phase < tetragonal phase < cubic phase . Presently, some transition‐metal oxides or conducting polymers are used as active materials for supercapacitors because they all participate in fast Faradic reactions between the active materials and electrolytes .…”

Section: Introductionmentioning

confidence: 99%

A New Facile Synthesis of Tungsten Oxide from Tungsten Disulfide: Structure Dependent Supercapacitor and Negative Differential Resistance Properties

Mandal

Routh²,

Nandi

2017

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Tungsten oxide (WO ) is an emerging 2D nanomaterial possessing unique physicochemical properties extending a wide spectrum of novel applications which are limited due to lack of efficient synthesis of high-quality WO . Here, a facile new synthetic method of forming WO from tungsten sulfide, WS is reported. Spectroscopic, microscopic, and X-ray studies indicate formation of flower like aggregated nanosized WO plates of highly crystalline cubic phase via intermediate orthorhombic tungstite, WO H O phase. The charge storage ability of WO is extremely high (508 F g at current density of 1 A g ) at negative potential range compared to tungstite (194 F g at 1 A g ). Moreover, high (97%) capacity retention after 1000 cycles and capacitive charge storage nature of WO electrode suggest its supremacy as a negative electrode of supercapacitors. The asymmetric supercapacitor, based on the WO as a negative electrode and mildly reduced graphene oxide as a positive electrode, manifests high energy density of 218.3 mWhm at power density 1750 mWm , and exceptionally high power density, 17 500 mW m , with energy density of 121.5 mWh m . Furthermore, the negative differential resistance (NDR) property of both WO and WO .H O are reported for the first time and NDR is explained with density of state approach.

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“…1739 " 42 (NH 4 );vV0 3: hexagonal Η,\¥0 3 + ΝΗ 3 (8) tetragonal (16) The large hole of the hexagonal lattice cannot exist any more after the NH 3 release and, because of the negligible size of the H + ion, tetragonal rearrangement takes place which yields a much smaller hole size. 1739 " 42 (NH 4 );vV0 3: hexagonal Η,\¥0 3 + ΝΗ 3 (8) tetragonal (16) The large hole of the hexagonal lattice cannot exist any more after the NH 3 release and, because of the negligible size of the H + ion, tetragonal rearrangement takes place which yields a much smaller hole size.…”

Section: Regions Of Existencementioning

confidence: 99%

Chemistry of Tungsten Oxide Bronzes

Bartha

Kiss

Szalay

1995

The Chemistry of Non-Sag Tungsten

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Ammonium paratungstate (APT) is the generally accepted starting material in tungsten manufacturing. The dopants, which are responsible for the non-sag properties, are given to some tungsten oxide bronze (TOB)-type compounds which are formed by thermal reductive decomposition of APT. The doped TOB is reduced in a H 2 atmosphere to tungsten metal grains. The powder metallurgical processing and the following thermomechanical treatment of the metal powder result in the formation of the non-sag wire.The bronze forming compounds (M z x ) in this case are NH4 or H + ions, or both of them, but the degree of reduction, i.e. the oxygen deficiency, may vary in the W0 3 , therefore, the description of the possible compounds seems to be necessary.We have the general formula of M ( / ) W0 3 _ > ,+z.Jt/2, where y^zx/2 conditions are possible. We also give a phase diagram in which we have located the possible types of compounds.The preparation methods of oxide bronzes (OBs) and the general structural characterization of OBs are described with special attention to ATOB and HTOB compounds. Because many experiences prove the advantages of ionexchange doping, such properties of TOBs have also been discussed.

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Phase Transitions in Sodium Tungsten Bronzes

Cited by 56 publications

References 0 publications

The crystal structure of K_0.54(Mn,Fe)F₃ at room temperature

The crystal structure of K_0.54(Mn,Fe)F₃ at room temperature

A New Facile Synthesis of Tungsten Oxide from Tungsten Disulfide: Structure Dependent Supercapacitor and Negative Differential Resistance Properties

Chemistry of Tungsten Oxide Bronzes

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Phase Transitions in Sodium Tungsten Bronzes

Cited by 56 publications

References 0 publications

The crystal structure of K0.54(Mn,Fe)F3 at room temperature

The crystal structure of K0.54(Mn,Fe)F3 at room temperature

A New Facile Synthesis of Tungsten Oxide from Tungsten Disulfide: Structure Dependent Supercapacitor and Negative Differential Resistance Properties

Chemistry of Tungsten Oxide Bronzes

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Product

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The crystal structure of K_0.54(Mn,Fe)F₃ at room temperature

The crystal structure of K_0.54(Mn,Fe)F₃ at room temperature