NO3(-) coordination in aqueous solutions by (15)N/(14)N and (18)O/(nat)O isotopic substitution: what can we learn...

We explore the deconvolution of water-nitrate correlations by the first-order difference approach involving neutron diffraction of heavy- and null-aqueous solutions of KNO3 under (14)N/(15)N and (nat)O(N)/(18)O(N) substitutions to achieve a full characterization of the first water coordination around the nitrate ion. For that purpose we performed isobaric-isothermal simulations of 3.5 m KNO3 aqueous solutions at ambient conditions to generate the relevant radial distribution functions required in the analysis (a) to identify the individual partial contributions to the total neutron-weighted distribution function, (b) to isolate and assess the contribution of NO3(-)···K(+) pair formation, (c) to test the accuracy of the neutron diffraction with isotope substitution based coordination calculations and X-ray diffraction based assumptions, and (d) to describe the water coordination around both the nitrogen and oxygen sites of the nitrate ion.