Molecular Rotation in the Solid State

Abstract

THE determined crystal structures of a number of primary alkyl ammonium halides indicate that in such compounds the carbon atoms are arranged collinearly¹ in a particular group. Thus in the case of primary amyl ammonium chloride² the X-ray diffraction data from powders and single crystals can be completely explained by a tetragonal unit of structure containing 2NH₃C₅H₁₁Cl with a = b = 5.01 A., c = 16.69 A. The space group is D₄², V_d³, S₄¹, C_4v¹ C₄¹ D_4h⁷, and the CI, N and C atoms are at o½u, ½oū, with u_cl = c. 0.095. The absence of reflections in odd orders from planes (hkO) with (h + k) odd and the intensities of reflections from other planes such as (200) require the carbon atoms of the C₅H₁₁ groups to scatter X-radiation as if they are arranged collinearly in each group.