Mobility and Reactions of VO2+ on Hydrated Smectite Surfaces1

Murray B. McBride
Department of Agronomy, Cornell University, Ithaca, New York 14853
1 Contribution of the Department of Agronomy, Cornell University, Ithaca, N.Y. 14853. Agronomy Paper No. 1251.

Abstract: The electron spin resonance (ESR) spectra of varying quantities of vanadyl ion (VO2+) adsorbed on hydrated hectorite indicated that hydrolysis of VO2+ was promoted at low levels of adsorption. The hydrolyzed product was adsorbed on the clay surfaces, with a ligand environment that was partially aqueous and partially hydroxide in nature. Greater amounts of VO2+ adsorbed on wetted hectorite obscured the ESR spectrum of the strongly adsorbed hydrolysis product with a solutionlike spectrum. An approximately 50% reduction in rotational mobility of VO2+ relative to solution was indicated by the linewidth of this spectrum. Loss in mobility occurred with reduction of the interlamellar spacing until, under strongly dehydrating conditions, the VO(H2O)52+ ions became aligned with the V=O bond axis normal to the plane of the clay platelets.

Key Words: Adsorption • ESR • Smectite • Vanadium

Clays and Clay Minerals; April 1979 v. 27; no. 2; p. 91-96; DOI: 10.1346/CCMN.1979.0270203
© 1979, The Clay Minerals Society
Clay Minerals Society (www.clays.org)