The effect of monovalent cations (Li+, K+, NH4 +, Na +) on the water structure
in aqueous chloride and acetate solutions was characterized by oxygen K-edge
X-ray absorption spectroscopy (XAS), X-ray emission spectroscopy, and resonant
inelastic X-ray scattering (RIXS) of a liquid microjet. We show ion- and
counterion dependent effects on the emission spectra of the oxygen K-edge,
which we attribute to modifications of the hydrogen bond network of water. For
acetates, ion pairing with carboxylates was also probed selectively by XAS and
RIXS. We correlate our experimental results to speciation data and to the
salting-out properties of the cations
