WordNet

a salt of tungstic acid

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2017/01/31 17:48:47」(JST)

wiki en

[Wiki en表示]

Chemical structure of the tungstate ion (WO2−

4)

In chemistry, a tungstate is a compound that contains an oxoanion of tungsten or is a mixed oxide containing tungsten. The simplest tungstate ion is WO2−
4, "orthotungstate".^[1] Many other tungstates belong to a large group of polyatomic ions that are termed polyoxometalates, ("POMs"), and specifically termed isopolyoxometalates as they contain, along with oxygen and maybe hydrogen, only one other element. Almost all useful tungsten ores are tungstates.^[2]

Structures

Orthotungstates feature tetrahedral W(VI) centres with short W–O distances of 1.79 Å. Structurally, they resemble sulfates. Six-coordinate, octahedral tungsten dominates in the polyoxotungstates. In these compounds, the W–O distances are elongated.^[1]

Some examples of tungstate ions:^[3]

HWO−
4 (hydrogentungstate)^[3]
polymeric W
2O2−
7 ions of various structures in Na₂W₂O₇, Li₂W₂O₇ and Ag₂W₂O₇^[4]
[W₇O₂₄]⁶⁻ (paratungstate A)^[3]
[W₁₀O₃₂]⁴⁻ (tungstate Y)^[5]
[H₂W₁₂O₄₂]¹⁰⁻ (paratungstate B) ^[3]
α-[H₂W₁₂O₄₀]⁶⁻ (metatungstate)^[5])
β-[H₂W₁₂O₄₀]⁶⁻ (tungstate X)^[5])

See the tungstates category for a list of tungstates.

Occurrence

Tungstates occur naturally with molybdates. Scheelite, the mineral calcium tungstate, often contains a small amount of molybdate. Wolframite is manganese and iron tungstate, and all these are valuable sources of tungsten. Powellite is a mineral form of calcium molybdate containing a small amount of tungstate.

Reactions

Solutions of tungstates, like those of molybdates, give intensely blue solutions of complex tungstate(V,VI) analoguous to the molybdenum blues when reduced by most organic materials.^[1]

Unlike chromate, tungstate is not a good oxidizer, but like chromate, solutions of tungstate condense to give the isopolytungstates upon acidification.

References

^ ^a ^b ^c Egon Wiberg, Arnold Frederick Holleman (2001). Inorganic Chemistry. Elsevier. ISBN 0-12-352651-5.
^ Erik Lassner, Wolf-Dieter Schubert, Eberhard Lüderitz, Hans Uwe Wolf "Tungsten, Tungsten Alloys, and Tungsten Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, 2000, Wiley-VCH, Weinheim. doi:10.1002/14356007.a27_229
^ ^a ^b ^c ^d Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 0-08-037941-9.
^ Wells A.F. (1984) Structural Inorganic Chemistry 5th edition Oxford Science Publications ISBN 0-19-855370-6
^ ^a ^b ^c Jon A. McCleverty, N. G. Connelly,Nomenclature of inorganic chemistry II: recommendations 2000, International Union of Pure and Applied Chemistry Commission on the Nomenclature of Inorganic Chemistry, Published by Royal Society of Chemistry, 2001, ISBN 0-85404-487-6

English Journal

In vivo sodium tungstate treatment prevents E-cadherin loss induced by diabetic serum in HK-2 cell line.

Bertinat R1,2, Silva P1, Mann E3, Li X3, Nualart F2, Yáñez AJ1,2.
Journal of cellular physiology.J Cell Physiol.2015 Oct;230(10):2437-46. doi: 10.1002/jcp.24974.
Diabetic nephropathy (DN) is characterized by interstitial inflammation and fibrosis, which is the result of chronic accumulation of extracellular matrix produced by activated fibroblasts in the renal tubulointerstitium. Renal proximal tubular epithelial cells (PTECs), through the process of epithel
PMID 25728412

Simultaneous speciation analysis of chromate, molybdate, tungstate and vanadate in welding fume alkaline extracts by HPLC-ICP-MS.

Ščančar J1, Berlinger B2, Thomassen Y2, Milačič R3.
Talanta.Talanta.2015 Sep 1;142:164-9. doi: 10.1016/j.talanta.2015.04.067. Epub 2015 Apr 30.
A novel analytical procedure was developed for the simultaneous speciation analysis of chromate, molybdate, tungstate and vanadate by anion-exchange high performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry (HPLC-ICP-MS). Linear gradient elution from 100% wate
PMID 26003707

Sodium tungstate induced neurological alterations in rat brain regions and their response to antioxidants.

Sachdeva S1, Pant SC1, Kushwaha P1, Bhargava R1, Flora SJ2.
Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association.Food Chem Toxicol.2015 Aug;82:64-71. doi: 10.1016/j.fct.2015.05.003. Epub 2015 May 14.
Tungsten, recognized recently as an environmental contaminant, is being used in arms and ammunitions as substitute to depleted uranium. We studied the effects of sodium tungstate on oxidative stress, few selected neurological variables like acetylcholinesterase, biogenic amines in rat brain regions
PMID 25983264

Japanese Journal

タングステンの溶解反応を用いたCuWO4の作製

鈴木菜々,世利修美
粉体および粉末冶金 62(4), 152-157, 2015
… ABSTRACT<BR><BR>Attempts have been made to obtain copper tungstate (CuWO4) powders by application of corrosion synthesis. …
NAID 130005066957

Control over Growth of Hexagonal Sodium Tungstate Nanorods by Poly (styrenesulfonate)

KIM Jungtae,MOOM Kyunghwan,CHOI Jaehyuk,YOO Pil J.,PARK Juhyun
Chemistry letters 42(10), 1149-1150, 2013-10-05
NAID 10031201291

Facile synthesis of WO3•H2O square nanoplates via a mild aging of ion-exchanged precursor

ELNOUBY Mohamed,KURUMA Kazuo,NAKAMURA Eri,ABE Hiroya,SUZUKI Yoshikazu,NAITO Makio
Journal of the Ceramic Society of Japan 121(1418), 907-911, 2013-10
… The ion-exchanged precursor was prepared by passing the sodium tungstate solution (Na2WO4) through a protonated cation-exchange resin, and used as impurity-free acidified solution (H2WO4) for synthesizing WO3·H2O nanoplates. …
NAID 120005396066