Tungsten blue
Crystal structure | |||||||
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__ W 5.5+ __ O 2− crystal structure of H 0.5 WO 3 |
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General | |||||||
Surname | Tungsten blue | ||||||
Ratio formula | H 0.5 WO 3 | ||||||
Brief description |
blue solid |
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External identifiers / databases | |||||||
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properties | |||||||
Molar mass | 232.42 g mol −1 | ||||||
Physical state |
firmly |
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density |
7.35 g cm −3 |
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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 . |
Tungsten blue is an inorganic chemical compound of tungsten from the group of oxide hydroxides . In addition to H 0.5 WO 3 , other tungsten oxide hydroxides of a certain composition and with oxidation numbers between 5 and 6 are referred to as tungsten blue because of the deep blue color of their solutions and correspond in many ways to molybdenum blue .
Extraction and presentation
Tungsten blue H 0.5 WO 3 is produced by the action of reducing agents on tungsten (VI) oxide .
properties
Tungsten blue H 0.5 WO 3 is a brown to violet powder that is very easy to oxidize. Upon contact with water, it oxidizes, releasing hydrogen. With slow oxidation, blue H 0.33 WO 3 and H 0.1 WO 3 can be obtained. H 0.5 WO 3 releases not only water but also hydrogen on thermal decomposition. It has a crystal structure of the DO 9 type with a slight tetragonal distortion.
use
Tungsten blue serves as evidence of tungstates (e.g. sodium tungstate ) or tungsten (VI) compounds, from which it is produced by reduction. It used to be called mineral blue and was used as a pigment in painting at the end of the 19th century.
Individual evidence
- ↑ a b c d e Georg Brauer: Handbook of preparative inorganic chemistry . 3., reworked. Edition. tape III . Enke, Stuttgart 1981, ISBN 3-432-87823-0 , pp. 1566 .
- ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
- ^ Gert Blumenthal, Dietmar Linke, Siegfried Vieth: Chemistry: Basic knowledge for engineers . Springer DE, 2006, ISBN 3-8351-9047-4 , p. 339 ( limited preview in Google Book search).
- ^ A b Heinrich Remy : Textbook of Inorganic Chemistry Volume II, Akademische Verlagsgesellschaft Geest & Portig Leipzig 1961, p. 218
- ^ Oskar Glemser, Christa Naumann: Crystallized tungsten blue compounds; Hydrogen analogues of tungsten bronzes HxWO3. In: Journal of Inorganic and General Chemistry. 265, 1951, pp. 288-302, doi : 10.1002 / zaac.19512650413 .
- ↑ Hans Peter Latscha, Helmut Alfons Klein: Analytical Chemistry: Basic Chemistry III . Springer DE, 2004, ISBN 3-642-18493-6 , pp. 88 ( limited preview in Google Book search).
- ^ Georg Schwedt: Chemical experiments in castles, monasteries and museums: From witch kitchen and ... John Wiley & Sons, 2012, ISBN 3-527-66132-8 , p. 222 ( limited preview in Google Book search).