Lithium tungstate

Crystal structure
__ Li +      __ Wo 6+      __ O 2−
Crystal system	Trigonal
Space group	R 3 (No. 148)
Lattice parameters	a = 8.888  Å , α = 107 ° 78 ′
General
Surname	Lithium tungstate
other names	Dilithium tetraoxotungstat Lithium tungsten oxide
Ratio formula	Li 2 WO 4
Brief description	colorless solid
External identifiers / databases
CAS number 13568-45-1 EC number 236-978-2 ECHA InfoCard 100.033.602 PubChem 5062350 Wikidata Q6647973
properties
Molar mass	261.72 g mol −1
Physical state	firmly
density	3.71 g cm −3 (25 ° C)
Melting point	742 ° C
solubility	soluble in water
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Lithium tungstate is an inorganic chemical compound of lithium from the group of tungstates .

Extraction and presentation

Lithium tungstate can be obtained by reacting tungsten (VI) oxide with a boiling solution of lithium carbonate .

properties

Lithium tungstate is a hygroscopic colorless solid that is soluble in water. It occurs in several modifications and at room temperature either has a crystal structure of the phenacite type with the space group R 3 (space group no. 148) . or a tetragonal crystal structure that corresponds to a distorted spinel structure with the space group I 4 ₁ / amd (No. 141) . At 40 kBar and 850 ° C it has a monoclinic crystal structure of the wolframite type with the space group C 2 / c (no. 15) .

use

Lithium tungstate is used for the production of ceramics with extremely low sintering temperatures . It also serves as a catalyst for oxidative coupling reactions . It is also used for the production of high-density aqueous poly tungstate (metatungstate) solutions that are used to separate minerals and other solids.

Individual evidence

1. ^ ^{A b} W. H. Zachariasen, HA Plettinger: The crystal structure of lithium tungstate. In: Acta Crystallographica. 14, 1961, p. 229, doi : 10.1107 / S0365110X61000772 .
2. ↑ ^{a b c d e} data sheet lithium tungstate from AlfaAesar, accessed on June 5, 2016 ( PDF )(JavaScript required) .
3. ↑ ^{a b c d} data sheet Lithium tungstate, 98% from Sigma-Aldrich , accessed on June 5, 2016 ( PDF ).
4. ^ RJ Meyer: Wolfram . Springer-Verlag, 2013, ISBN 978-3-662-13401-6 , pp. 208 ( limited preview in Google Book search).
5. ↑ Mohd Rafie Johan, Tan Kim Han, Abdul Kariem Arof: Growth and sintering effects of hydrated polycrystalline Li ₂ WO ₄ . In: Ionics. 16, 2010, p. 323, doi : 10.1007 / s11581-009-0407-4 .
6. ^ Evgeni Tonkov: High Pressure Phase Transformations A Handbook . CRC Press, 1992, ISBN 978-2-88124-759-0 , pp. 534 ( limited preview in Google Book search).
7. ↑ Hiroyuki Horiuchi, Nobuo Morimoto, Shinobu Yamaoka: The crystal structure of Li ₂ WO ₄ (IV) and its relation to the wolframite-type structure. In: Journal of Solid State Chemistry. 33, 1980, p. 115, doi : 10.1016 / 0022-4596 (80) 90554-X .