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 04:00:00 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), Journal Name: Journal of the Electrochemical Society; (United States) Vol. 140:10; ISSN 0013-4651; ISSN JESOAN
• Country of Publication: United States
• Language: English

Related Subjects

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