Vibrational spectra of anhydrous scandium(III) chloride and bromide and their complexes

Abstract

The far-i.r. spectra of anhydrous ScCl₃ and ScBr₃(and the Raman spectrum of the former) are reported. Four well defined pyridine complexes having 1 : 4 and 1 : 3 stoicheiometry were characterized. ScCl₃,4py and ScBr₃,4py have one loosely bound, non-co-ordinated pyridine molecule, [py₃ScX₃]py. The 1 : 3 complex py₃,ScCl₃ appears to be a cis(facial)-octahedral complex which is only weakly ionized in nitromethane solutions, whereas the corresponding bromo-complex behaves as a strongly ionized tetrahedral complex [py₃ScBr]²⁺(Br^–)₂. The first phosphine complexes of scandium are also reported: ScCl₃,dppe and ScBr₃,1·5dppe [dppe = 1,2-bis(diphenylphosphino)ethane]. Their far-i.r. spectra are presented and possible structures are discussed.