Crystal Structure of Zirconium Tungstate

The arrangement of the groups in the structure of cubic ZrW2O8 is analogous to the simple NaCl structure, with ZrO6 octahedral at the Na sites, and W2O8 groups at the Cl sites. The unit cell consists of 44 atoms aligned in a primitive cubic Bravais lattice, with unit cell length 9.15462 Angstroms.

The ZrO6 octahedral are only slightly distorted from a regular conformation, and all oxygen sites in a given octahedron are related by symmetry. The W2O8 unit is made up of two crystallographic ally distinct WO4 tetrahedral, which are not formally bonded to each other. These two types of tetrahedral differ with respect to the W-O bond lengths and angles. The WO4 tetrahedral are distorted from a regular shape since one oxygen is unconstrained (an atom that is bonded only to the central tungsten (W) atom), and the three other oxygen’s are each bonded to a zirconium atom (i.e. the corner-sharing of polyhedral).

The structure has P213 space group symmetry at low temperatures. At higher temperatures, a centre of inversion is introduced by the disordering of the orientation of tungstate groups, and the space group above the phase transition temperature (~180C) is Pa .

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Zirconium Tungstate Definition by Wiki

At high pressure, zirconium tungstate undergoes a series of phase transitions, first to an amorphous phase, and then to a U3O8-type phase, in which the zirconium and tungsten atoms are disordered.

Zirconium tungstate (Zr(WO4)2) is a metal oxide with unusual properties. The phase formed at ambient pressure by reaction of ZrO2and WO3 is a metastable cubic phase, which has negative thermal expansion characteristics, namely it shrinks over a wide range of temperatures when heated. In contrast to most other ceramics exhibiting negative CTE (coefficient of thermal expansion), the CTE of ZrW2O8 is isotropic and has a large negative magnitude (average CTE of -7.2x10−6K−1) over a wide range of temperature (-273 °C to 777 °C). A number of other phases are formed at high pressures.

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about ammonium paratungstate (APT)

Ammonium paratungstate, (APT) is a white crystalline salt of ammonium and tungsten.

APT is produced by separating tungsten from its ore. Once the ammonium paratungstate is prepared, it is heated to its decomposition temperature, 600 °C. Left over is WO₃, tungsten oxide. At that point, the oxide is heated in an atmosphere of hydrogen, reducing the tungsten to powder, leaving behind water vapor. From there, the tungsten metal powder can be fused into any number of things, from wire to bars to other shapes.

The WO3 content of APT manufactured and supplied by Chinatungsten Online is over 88.5%.

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What does APT stand for?

What does APT stand for?

In tungsten industry, APT is stand for ammonium paratungstate, whose chemical formula is 5(NH4)2O.12WO3.xH2O. APT is produced separating tungsten from its ore. APT is heated to its decomposition temperature, 600 °C. Left over is WO3, called tungsten trioxide. Tungsten oxide is heated in an atmosphere of hydrogen, reducing the tungsten to elemental powder--tungsten powder. The tungsten powder can be fused into any number of things, from wire to rods to other shapes.

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tungsten oxide with nanostructure

Metal oxides are the key ingredients for the development of many advanced functional materials and smart devices. Nanostructuring has emerged as one of the best tools to unlock their full potential. Tungsten oxides (WO_x) are unique materials that have been rigorously studied for their chromism, photocatalysis, and sensing capabilities. However, they exhibit further important properties and functionalities that have received relatively little attention in the past. This Feature Article presents a general review of nanostructured WO_x, their properties, methods of synthesis, and a description of how they can be used in unique ways for different applications.
Nano tungsten oxide particles are produced by wire explosion process. It is realized that by exploding tungsten conductor in lower pressure of oxygen, unreacted phase of tungsten was present and it could be reduced by increasing the operating pressure and increasing the amount of energy deposited to the exploding conductor. 

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Tungsten Oxide Powder Synonyms

Tungsten oxide powder is called tungsten oxide , is compound of tungsten and oxygen.

Tungsten Oxide Powder Synonyms as following:
tungsten oxide, tungsten(IV) oxide (WO2), tungsten(VI) oxide (WO3), tungsten trioxide, tungsten(VI) trioxide, tungstic anhydride (WO3), ditungsten pentaoxide, tetratungsten undecaoxide, tungsten oxide, tungsten oxide (W2O5), scheelite, wolframite, ferberitetungsten oxide (W4O11),  
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about Tungsten Oxide Film

Thermodynamically, tungsten trioxide (WO3) is reported to be stable in acidic
environments. However, the relatively high dissolution rate of WO3 in acidic solution has long been recognized by those investigating the mechanism of WO3
 coloration (electrochromism) for application in the flat panel display industry(2). To date the exact mechanism by which this dissolution process occurs remains elusive. While in alkaline environments the dissolution of WO3 is both thermodynamically favorable and experimentally observed, there has been no generalgreement on the dissolution mechanism. To examine oxide composition, structure, and hydration as a function of solution pH and applied potential in situ, surface enhanced Raman spectroscopy was employed. In addition,electrochemical impedance spectroscopy was used in conjunction with rotating disk electrode experiments to examine the effects of mass transport on the native tungsten oxides as a function of solution pH and applied potential.

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