Influence of Charge Distribution on the Properties of Keggin- and Dawson-Type Heteropolyanions

✍ Scribed by Bineta Keita; Yu Wei Lu; Louis Nadjo; Roland Contant

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 470 KB
• Volume: 2000
• Category: Article
• ISSN: 1434-1948
• DOI: 10.1002/1099-0682(200012)2000:12<2463::aid-ejic2463>3.0.co;2-e

✦ Synopsis

The cyclic voltammetric behavior of selected Keggin-and Dawson-type heteropolyanions has been studied as a function of electrolyte composition. The buffer capacity of the electrolyte is shown to be an important parameter that can be used to reveal the symmetry or dissymetry in charge distribution within each oxometalate. A fully symmetrical heteropolyanion like [P 2 W 18 O 62 ] 6-exhibits a uniform protonability, while its α 1 and α 2 lacunary derivatives present a donor set of hard oxide ions with stepwise acid-base equilibria. The behavior of these sites is revealed readily in unbuffered or poorly buffered media at pH = 3, and is ascribed to the [