On NO−3–H2O interactions in aqueous solutions

The scattering of x rays from a concentrated NH4NO3 aqueous solution has been measured and analyzed at 25°C. It is shown that the sample may be considered as a solution of nitrate ions in water. In this way the existence of discrete NO−3–H2O interactions is demonstrated unequivocally. Good agreement with experimental data is achieved through a model in which each O atom in the nitrate ion gives rise to three weak hydrogen bonds with water molecules.