Zirconium tungstate
Crystal structure | |||||||||||||
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green octahedron: ZrO 6 ; red tetrahedra: WO 4 ; red spheres: oxygen atoms | |||||||||||||
General | |||||||||||||
Surname | Zirconium tungstate | ||||||||||||
other names |
Zirconium tungstate |
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Ratio formula | Zr (WO 4 ) 2 | ||||||||||||
Brief description |
white odorless powder |
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External identifiers / databases | |||||||||||||
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properties | |||||||||||||
Molar mass | 586.92 g mol −1 | ||||||||||||
Physical state |
firmly |
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density |
5.1 g cm −3 |
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solubility |
almost insoluble in water |
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safety instructions | |||||||||||||
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As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . |
Zirconium tungstate (Zr [WO 4 ] 2 ) is a chemical compound of zirconium , tungsten and oxygen and thus a compound from the group of tungstates .
Extraction and presentation
Zirconium tungstate can be obtained by reacting zirconium (IV) oxide and tungsten (VI) oxide .
properties
A very characteristic peculiarity of zirconium tungstate is the density anomaly . It contracts when heated, unlike most other substances. This behavior occurs between −270 ° C (3.15 Kelvin ) and 777 ° C, the linear expansion is −8.7 · 10 −6 K −1 . Some other materials have such a “reverse” temperature behavior, but they show it within a much smaller temperature range.
application
As a filler, it can partially or completely compensate for the positive temperature expansion of a matrix material, which results in materials with low thermal expansion.
Individual evidence
- ↑ a b c d e data sheet zirconium tungstate from AlfaAesar, accessed on December 26, 2019 ( PDF )(JavaScript required) .
- ↑ Solid body with negative thermal expansion
- ↑ Wayne Weyer et al .: Achieving Dimensional Stability Using Functional Fillers , Conference Paper 46th AIAA / ASME / ASCE / AHS / ASC Structures, Structural Dynamics and Materials Conference, doi : 10.2514 / 6.2005-2091 .