NEUTRON DIFFRACTION STUDY OF THE CRYSTAL STRUCTURE OF AMMONIUM CHLORIDE

摘要: The crystal structure of the room-temperature phase ammonium chloride has been determined by powder and single neutron diffraction methods. N---H links are directed essentially toward four eight surrounding ions, and, contrary to a recent report, two orientations fulfilling this condition occupied at random in crystal. Thermal motion hydrogen atoms is nonspherical suggests rotatory oscillation ion as whole with half-angle about 10\ifmmode^\circ\else\textdegree\fi{}. length link 1.03\ifmmode\pm\else\textpm\fi{}0.02 $A$. second-order transition -30\ifmmode^\circ\else\textdegree\fi{}C thus shown be order-disorder type.