Tungsten blue

Crystal structure
__ W 5.5+      __ O 2− crystal structure of H 0.5 WO 3
General
Surname	Tungsten blue
Ratio formula	H 0.5 WO 3
Brief description	blue solid
External identifiers / databases
CAS number 39422-57-6 Wikidata Q13846459
properties
Molar mass	232.42 g mol −1
Physical state	firmly
density	7.35 g cm −3
safety instructions
GHS hazard labeling no classification available
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

1. ↑ ^{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 .
2. ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
3. ^ 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).
4. ^ ^{A b} Heinrich Remy : Textbook of Inorganic Chemistry Volume II, Akademische Verlagsgesellschaft Geest & Portig Leipzig 1961, p. 218
5. ^ 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 .
6. ↑ 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).
7. ^ 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).