Resolving ruthenium: XPS studies of common ruthenium materials

X‐ray photoelectron spectroscopy (XPS) utilising monochromatic Al K α radiation has been employed to study metallic ruthenium and the catalytically and technologically important ruthenium compounds RuO 2 , RuCl 3 , Ru(NO)(NO 3 ) 3 and Ru(AcAc) 3 . The results improve on the accuracy of already published Ru(3d) binding energies, expand known Ru(3p) binding energies and also report spin‐orbit splitting for the core levels. For RuO 2 , the difference between anhydrous and hydrated samples is explored, and the effect on curve fitting such spectra is discussed. Analysis of RuCl 3 has allowed, for the first time, the positive identification of Ru(OH) 3 by XPS. Copyright © 2015 John Wiley & Sons, Ltd.