Ammonium ion coordination in concentrated aqueous ammonium chloride

Results of a neutron-diffraction study on 5.0 molal ammonium chloride in heavy water were used to determine the ND⁺₄ water conformation. There are between 10 and 11 water molecules coordinated to the ammonium ion in the range 2.60–4.35 Å. The coordination is not well defined and although in broad agreement with a molecular dynamics study, there are significant differences.