Spectroscopic and electrochemical studies of tungsten(VI) and Tungsten(V) chloride and oxychloride complexes in a sodium chloride saturated sodium chloroaluminate melt

Journal Article · Fri Oct 01 00:00:00 EDT 1993 · Journal of the Electrochemical Society; (United States)

DOI:https://doi.org/10.1149/1.2220901· OSTI ID:5998639

Sun, I W; Edwards, A G; Mamantov, G ^[1]

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1. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry

Raman and UV-visible absorption spectroscopies indicate that the addition of WCl[sub 6] or KWCl[sub 6] to a sodium chloride saturated sodium chloroaluminate melt at 175 C produces the tungsten (V) hexachloride anion [WCl[sub 6]][sup [minus]] can be oxidized to WCl[sub 6] via a reversible one-electron charge-transfer process with a voltammetric half-wave potential of 2.077 V referenced to aluminum in a pure sodium chloride saturated sodium chloroaluminate melt. With fast scan rate voltammetry, [WCl[sub 6]][sup [minus]] can be reduced to [WCl[sub 6]][sup 2[minus]] and [WCl[sub 6]][sup 3[minus]] via two consecutive one-electron reduction processes with half-wave potentials of 1.578 and 0.818 V, respectively. Both [WCl[sub 6]][sup 2[minus]] and [WCl[sub 6]][sup 3[minus]] form precipitates in this melt at this temperature. Using slow scan rate voltammetry, the reduction processes are complicated by coupled chemical reactions. Tungsten (VI) oxychloride, WOCl[sub 4], is stable in this melt, and can be reduced to tungsten (V) oxychloride via a reversible one-electron reduction process with a half-wave potential of 1.746 V. Absorption spectroscopy shows that the tungsten(V) chloride is [WOCl[sub 5]][sup 2[minus]]. Fast scan rate voltammetry indicates that tungsten (V) oxychloride exhibits a two-electron reduction process to produce a W(III) species. At slow scan rates, the reduction appears to be complicated by coupled chemical reactions. Definitive characterization of the reduction mechanisms is prevented by film formation on the electrode surface during these reductions.

• OSTI ID: 5998639
• Journal Information: Journal of the Electrochemical Society; (United States), Vol. 140:10; ISSN 0013-4651
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
TUNGSTEN CHLORIDES
ABSORPTION SPECTROSCOPY
ELECTROCHEMISTRY
RAMAN SPECTROSCOPY
MOLTEN SALTS
OXYCHLORIDES
REDUCTION
SODIUM CHLORIDES
TUNGSTEN COMPOUNDS
ULTRAVIOLET RADIATION
VISIBLE RADIATION
VOLTAMETRY
ALKALI METAL COMPOUNDS
CHEMICAL REACTIONS
CHEMISTRY
CHLORIDES
CHLORINE COMPOUNDS
ELECTROMAGNETIC RADIATION
HALIDES
HALOGEN COMPOUNDS
LASER SPECTROSCOPY
OXYGEN COMPOUNDS
OXYHALIDES
RADIATIONS
REFRACTORY METAL COMPOUNDS
SALTS
SODIUM COMPOUNDS
SPECTROSCOPY
TRANSITION ELEMENT COMPOUNDS
400400* - Electrochemistry
400102 - Chemical & Spectral Procedures