Electrochemistry of Niobium Chloride and Oxide Chloride Complexes in the Basic Aluminum Chloride- l-Methyl-3-ethylimidazolium Chloride Room-Temperature Ionic Liquid

I-Wen Sun, Charles L. Hussey

Research output: Contribution to journalArticle

61 Citations (Scopus)

Abstract

Niobium(V) is complexed as [NbCI6]- in the basic aluminum chloride-l-methyl-3-ethylimidazolium chloride ionic liquid, and it can be reduced to [NbCl6]2~ and [NbCl6]3 4 N~ in successive, one-electron, reversible redox reactions at a glassy-carbon electrode with voltammetric half-wave potentials of 0.17 and -0.93 V, respectively, in the 44.4/55.6 mol % melt at 40 °C, referenced to aluminum in the 66.7/33.3 mol % melt. The average Stokes-Einstein products for [NbCl6]- and [NbCl6]2- in the ionic liquid are 3.5 X 10~10and 2.1 X 10–10cm s-2K-1, respectively. The addition of oxide ion to solutions of [NbCl6]- in basic melt produces [NbOCl5]2-. This species can be electrochemically reduced to a strongly paramagnetic monomeric niobium(IV) species, which is associated with a single oxide ion, possibly [NbOCl4]2- or [NbOCl5]3-. The niobium(V)/niobium(IV) oxide chloride electrode reaction exhibits quasireversible behavior with a standard heterogeneous rate constant of 9.0 X 10-7cm s-1and a cathodic transfer coefficient of ca. 0.8. The formal electrode potential of the niobium(V)/niobium(IV) oxide chloride redox couple is -0,521 V in the 44.4/55.6 mol % melt. The Stokes-Einstein products of [NbOCl5]2_and the related niobium(IV) oxide chloride complex are 1.9 X 10-I° and 1.4 X 10-10cm s~2K-1, respectively. The overall electrochemical scheme for niobium complexes in the AlCl3-MeEtimCl ionic liquid is summarized as follows.

Original languageEnglish
Pages (from-to)2731-2737
Number of pages7
JournalInorganic Chemistry
Volume28
Issue number14
DOIs
Publication statusPublished - 1989 Jul 1

Fingerprint

Niobium
aluminum chlorides
Ionic Liquids
Electrochemistry
electrochemistry
niobium
Oxides
Chlorides
chlorides
oxides
room temperature
liquids
Temperature
Electrodes
electrodes
Ions
aluminum chloride
Redox reactions
glassy carbon
Glassy carbon

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

Cite this

@article{39fdf496487d4eee955e21ed903aa255,
title = "Electrochemistry of Niobium Chloride and Oxide Chloride Complexes in the Basic Aluminum Chloride- l-Methyl-3-ethylimidazolium Chloride Room-Temperature Ionic Liquid",
abstract = "Niobium(V) is complexed as [NbCI6]- in the basic aluminum chloride-l-methyl-3-ethylimidazolium chloride ionic liquid, and it can be reduced to [NbCl6]2~ and [NbCl6]3 4 N~ in successive, one-electron, reversible redox reactions at a glassy-carbon electrode with voltammetric half-wave potentials of 0.17 and -0.93 V, respectively, in the 44.4/55.6 mol {\%} melt at 40 °C, referenced to aluminum in the 66.7/33.3 mol {\%} melt. The average Stokes-Einstein products for [NbCl6]- and [NbCl6]2- in the ionic liquid are 3.5 X 10~10and 2.1 X 10–10cm s-2K-1, respectively. The addition of oxide ion to solutions of [NbCl6]- in basic melt produces [NbOCl5]2-. This species can be electrochemically reduced to a strongly paramagnetic monomeric niobium(IV) species, which is associated with a single oxide ion, possibly [NbOCl4]2- or [NbOCl5]3-. The niobium(V)/niobium(IV) oxide chloride electrode reaction exhibits quasireversible behavior with a standard heterogeneous rate constant of 9.0 X 10-7cm s-1and a cathodic transfer coefficient of ca. 0.8. The formal electrode potential of the niobium(V)/niobium(IV) oxide chloride redox couple is -0,521 V in the 44.4/55.6 mol {\%} melt. The Stokes-Einstein products of [NbOCl5]2_and the related niobium(IV) oxide chloride complex are 1.9 X 10-I° and 1.4 X 10-10cm s~2K-1, respectively. The overall electrochemical scheme for niobium complexes in the AlCl3-MeEtimCl ionic liquid is summarized as follows.",
author = "I-Wen Sun and Hussey, {Charles L.}",
year = "1989",
month = "7",
day = "1",
doi = "10.1021/ic00313a009",
language = "English",
volume = "28",
pages = "2731--2737",
journal = "Inorganic Chemistry",
issn = "0020-1669",
publisher = "American Chemical Society",
number = "14",

}

TY - JOUR

T1 - Electrochemistry of Niobium Chloride and Oxide Chloride Complexes in the Basic Aluminum Chloride- l-Methyl-3-ethylimidazolium Chloride Room-Temperature Ionic Liquid

AU - Sun, I-Wen

AU - Hussey, Charles L.

PY - 1989/7/1

Y1 - 1989/7/1

N2 - Niobium(V) is complexed as [NbCI6]- in the basic aluminum chloride-l-methyl-3-ethylimidazolium chloride ionic liquid, and it can be reduced to [NbCl6]2~ and [NbCl6]3 4 N~ in successive, one-electron, reversible redox reactions at a glassy-carbon electrode with voltammetric half-wave potentials of 0.17 and -0.93 V, respectively, in the 44.4/55.6 mol % melt at 40 °C, referenced to aluminum in the 66.7/33.3 mol % melt. The average Stokes-Einstein products for [NbCl6]- and [NbCl6]2- in the ionic liquid are 3.5 X 10~10and 2.1 X 10–10cm s-2K-1, respectively. The addition of oxide ion to solutions of [NbCl6]- in basic melt produces [NbOCl5]2-. This species can be electrochemically reduced to a strongly paramagnetic monomeric niobium(IV) species, which is associated with a single oxide ion, possibly [NbOCl4]2- or [NbOCl5]3-. The niobium(V)/niobium(IV) oxide chloride electrode reaction exhibits quasireversible behavior with a standard heterogeneous rate constant of 9.0 X 10-7cm s-1and a cathodic transfer coefficient of ca. 0.8. The formal electrode potential of the niobium(V)/niobium(IV) oxide chloride redox couple is -0,521 V in the 44.4/55.6 mol % melt. The Stokes-Einstein products of [NbOCl5]2_and the related niobium(IV) oxide chloride complex are 1.9 X 10-I° and 1.4 X 10-10cm s~2K-1, respectively. The overall electrochemical scheme for niobium complexes in the AlCl3-MeEtimCl ionic liquid is summarized as follows.

AB - Niobium(V) is complexed as [NbCI6]- in the basic aluminum chloride-l-methyl-3-ethylimidazolium chloride ionic liquid, and it can be reduced to [NbCl6]2~ and [NbCl6]3 4 N~ in successive, one-electron, reversible redox reactions at a glassy-carbon electrode with voltammetric half-wave potentials of 0.17 and -0.93 V, respectively, in the 44.4/55.6 mol % melt at 40 °C, referenced to aluminum in the 66.7/33.3 mol % melt. The average Stokes-Einstein products for [NbCl6]- and [NbCl6]2- in the ionic liquid are 3.5 X 10~10and 2.1 X 10–10cm s-2K-1, respectively. The addition of oxide ion to solutions of [NbCl6]- in basic melt produces [NbOCl5]2-. This species can be electrochemically reduced to a strongly paramagnetic monomeric niobium(IV) species, which is associated with a single oxide ion, possibly [NbOCl4]2- or [NbOCl5]3-. The niobium(V)/niobium(IV) oxide chloride electrode reaction exhibits quasireversible behavior with a standard heterogeneous rate constant of 9.0 X 10-7cm s-1and a cathodic transfer coefficient of ca. 0.8. The formal electrode potential of the niobium(V)/niobium(IV) oxide chloride redox couple is -0,521 V in the 44.4/55.6 mol % melt. The Stokes-Einstein products of [NbOCl5]2_and the related niobium(IV) oxide chloride complex are 1.9 X 10-I° and 1.4 X 10-10cm s~2K-1, respectively. The overall electrochemical scheme for niobium complexes in the AlCl3-MeEtimCl ionic liquid is summarized as follows.

UR - http://www.scopus.com/inward/record.url?scp=0009425397&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0009425397&partnerID=8YFLogxK

U2 - 10.1021/ic00313a009

DO - 10.1021/ic00313a009

M3 - Article

VL - 28

SP - 2731

EP - 2737

JO - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

IS - 14

ER -