FTIR study of HCN adsorption on magnesium fluoride

Abstract

The mechanism of HCN interaction with MgF2 pretreated at 773 K has been studied by means of FTIR spectroscopy at 77–300 K. The properties of surface sites were preliminary characterized by the low temperature spectra of adsorbed CO, which reveal the presence of several types of Lewis acid sites of different strength, weak H-bond with surface OH-groups, as well as interaction with surface anions. Adsorption of isotopically substituted molecules: DCN, H13C14N and H12C15N facilitates the assignment of absorption bands and has shown that hydrogen cyanide does not dissociate on adsorption. Adsorbed molecules form coordinate bond with surface cations, interact with surface hydroxyls or form weak H-bond by the CH-group with the anions, apparently, with surface F− ions.