We have demonstrated experimentally by Raman analysis that 1a exists as a mixture of ttt/cct conformers at 22°C in liquid or CCl₄ solution, thus contrasting with the initial IR, NMR and X-ray analyses, which were strongly in favour of (ttt)-1a. The global stereoelectronic stabilization is ca. 4.0-4.2 kcal/mol for both parallel N lone pairs (lp) in (cct)-1a, based on a ΔH of 0.75 kcal/mol (±10%), as measured by Raman spectroscopy from 22 to 90°C, as well as the roughly estimated MM2 MeNHEt and MeNHCH₂NH₂ gauche interactions. DFT calculations using B3LYP/6-31G^* yield a standard ΔH value of 1.04 kcal/mol, in good agreement with the experiment, and predict a ttt/cct ratio of ca. 77:23 at 25°C. Broadening of the ¹³C-NMR signals was observed in either CCl₄ or CS₂ or even CDCl₃ solutions between -20 and -40°C.