Sodium poly tungstate

General
Surname	Sodium poly tungstate
other names	Sodium metatungstate; hexa-sodium tungstate (W 12 );
Molecular formula	3 Na 2 WO 4 · 9 WO 3 · H 2 O
Brief description	white odorless solid
External identifiers / databases
EC number	412-770-9
ECHA InfoCard	100.101.205
Wikidata	Q7553361
properties
Molar mass	2986.01 g mol −1
Physical state	firmly
density	3.1 g cm −3 (20 ° C, saturated solution)
safety instructions
H and P phrases	H: 302-318-412
	P: 273-280-305 + 351 + 338
Toxicological data	1715 mg kg −1 ( LD 50 , rat , oral ) ; > 2000 mg kg −1 ( LD 50 , rabbit , transdermal ) ;
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Sodium polytungstate (also sodium metatungstate , engl. Sodium polytungstate , short SPT) is a relatively new agent for the production of a heavy liquid .

properties

In the solid state, SPT is a white, crystalline powder or, in an aqueous solution, a light yellow-green, transparent liquid. In crystalline form, it is a 12-fold aggregated isopoly tungstate with a molar mass of 2986.12 g mol ⁻¹ . According to the models, the poly tungstate is made up of octahedra, with the oxygen ions at the corners and the tungsten ions in the middle of the octahedra. In the representation as a spherical model, the oxygen ions form the closest packing of spheres, with the tungsten ions in the respective octahedral gaps. According to the structure, this compound is a so-called "real" metatungstate with the formula Na ₆ [H ₂ W ₁₂ O ₄₀ ]. It is known from the real metatungstates that the two hydrogen atoms are present in the central cavity of the polyanion and cannot penetrate the spherical shell.

use

Due to its extremely high solubility in water (max. Density up to 3.1 g · cm ⁻³ ) it is suitable as a heavy liquid.

SPT is non-toxic, non-flammable, odorless and, as a solution, also has a very low viscosity, although the high-concentration solutions already have relatively high viscosities.

Individual evidence

↑ ^a ^b ^c Entry on hexasodium tungstate hydrate in the GESTIS substance database of the IFA , accessed on July 23, 2016(JavaScript required) .
↑ ^a ^b ^c ^d data sheet Sodium polytungstate, purum p. a., for the preparation of heavy liquid, for sink-float analysis, ≥85% WO from Sigma-Aldrich , accessed on March 10, 2013 ( PDF ).
↑ Entry on Hexasodium tungstate hydrate in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on August 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
^ ^A ^b Heinrich Schubert: Handbook of Mechanical Process Engineering . John Wiley & Sons, 2012, ISBN 3-527-66103-4 , pp. 621 ( limited preview in Google Book search).
↑ TC-Tungsten Compounds: Sodium Poly tungstate / Sodium Metatungstate information sheet
↑ Murray R. Gregory and Keith A. Johnston: A nontoxic substitute for hazardous heavy liquids — aqueous sodium polytungstate (3Na2WO4.9WO3.H2O) solution (Note) . In: New Zealand Journal of Geology and Geophysics . tape 30 , no. 3 , 1987, pp. 317 , doi : 10.1080 / 00288306.1987.10552626 (English).

[GESTIS-1] Entry on hexasodium tungstate hydrate in the GESTIS substance database of the IFA , accessed on July 23, 2016(JavaScript required) .

[Sigma-2] ta sheet Sodium polytungstate, purum p. a., for the preparation of heavy liquid, for sink-float analysis, ≥85% WO from Sigma-Aldrich , accessed on March 10, 2013 ( PDF ).

[CLP_100.101.205-3] Entry on Hexasodium tungstate hydrate in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on August 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .

[Heinrich_Schubert-4] A ^b Heinrich Schubert: Handbook of Mechanical Process Engineering . John Wiley & Sons, 2012, ISBN 3-527-66103-4 , pp. 621 ( limited preview in Google Book search).

[TC-Tungsten_Compounds-5] TC-Tungsten Compounds: Sodium Poly tungstate / Sodium Metatungstate information sheet

[6] Murray R. Gregory and Keith A. Johnston: A nontoxic substitute for hazardous heavy liquids — aqueous sodium polytungstate (3Na2WO4.9WO3.H2O) solution (Note) . In: New Zealand Journal of Geology and Geophysics . tape 30 , no. 3 , 1987, pp. 317 , doi : 10.1080 / 00288306.1987.10552626 (English).