(CH_3)_2NH_2~+ C_2N_4O_3H~- was prepared by mixing 3-nitro-l,2,4- triazol-5-one (NTO) etbanol solution and the dimethylamine aqueous solution. Single ciystals suitable for X-ray measurement were obtained by recrystallization with the mixed solvent of dimethyl formamide and methanol ( V:V = 1 : 5) at room temperature. The crystal is monoclinic, space group P2(l)/c with crystal parameters of a =0.7116(1) nm, b =0. 8735(2) nm, c = 1.3160 (3) nm, β= 101.12(2)°, V = 0.8026(3) nm~3, D_c = 1.450 g/cm~3, Z=4 and F(000) =368. The theoretical investigation of the title compound as stmeture unit was carried out by HF/6-31 + G(d), MP2/6-31 + G(d) and B3LYP/6-31 + G(d) methods, and the atomic net charges and the population analysis have been discussed.

Key words: TRIADIMEFON, NITRO COMPOUNDS, DIMETHYLAMINE, DIMETHYLAMINE P, CRYSTAL STRUCTURE, XRD, STABILITY