The Structure of Ammonium Chloride by Neutron Diffraction

Abstract

From the intensities of powder diffraction lines the positions of the deuterons in N${\mathrm{D}}_{4}$Cl have been determined at liquid nitrogen and room temperatures. The experimental results confirm at low temperature the space group $T_{d}^{}{}_{}{}^{1}$ and the tetrahedral structure of the ammonium ion with an $N\ensuremath{-}D$ separation 1.03A. At room temperature the $T_{d}^{}{}_{}{}^{1}$ space group persists. Neither free rotation nor disordered orientations of the ammonium ions have been observed. Details concerning deuteron vibrations are discussed.