The surface acidity of solid oxides and its characterization by IR spectroscopic methods. An attempt at systematization

The bases of IR spectroscopic methods for the characterization of the surfa ce acidity, of the Lewis type and of the Bronsted type, of solid, simple an d mixed oxides are briefly reviewed. The results are described and a system atization is proposed. The surface acidity is essentially associated with t he ionicity/covalency of the element-oxygen bond, mainly affected by the si ze and charge of the cation.