Vibrational Spectra and the Structure of Crystalline Triethylenediamine

The crystal structure of the symmetric-top molecule, triethylenediamine, is discussed in terms of the analysis of three-dimensional x-ray diffraction data in the space groups P63/m and P63. It was possible in the two cases to refine to slightly different structures with different molecular and site symmetries. The centrosymmetric structure with molecular symmetry D3h—6̄m2 was used as the basis for an analysis of the infrared spectrum of the crystal and the assignment of the prominent bands. The Raman spectrum of the molecule in solution and the infrared spectrum of a crystalline monohydrate are also reported.