A neutron powder diffraction study of ND₃ intercalated titanium disulfide, 3R-TiS₂ND₃

Neutron powder diffraction of rhombohedral 3R-TiS₂ND₃ (a = 3.419 Å, c = 27.03 Å at 300 K, space group R3m) has shown that ND₃ molecules and ND⁺₄ ions, present in a ratio of about 5 to 1 from chemical and physical evidence, occupy statistically the trigonal-prismatic holes between TiS₂ sandwiches. One cannot distinguish between ND₃ and ND⁺₄. Powder intensities calculated for a model with spherically symmetric ND₃ molecules (corresponding to isotropically rotating ND₃ and ND⁺₄) in the trigonal-prismatic holes were in reasonable agreement with the observed intensities. Attempts to obtain information on the precise orientation of ND₃ and ND⁺₄ in the TiS₂ lattice using refinements with structure factors were not successful; the reliability R factor was 0.093 for spherical symmetric ND₃ molecules with nitrogen in the center of the trigonal-prismatic holes.