Several new energetic low-melting monosubstituted polynitroalkoxy-1,2,4,5-tetrazines have been synthesized. Their thermal stability has been investigated by the methods of isothermal and non-isothermal kinetics. These molecules display good thermal stability: trinitroethoxytetrazine can be safely kept in the molten state for about a week, dinitro-fluoroethoxy derivative is significantly more stable. The volatility of the studied compounds increases in the series of substituents asThe vapor pressure over the liquid fluorine derivative turned out to be 2 times less than the vapor pressure over the liquid trinitroazetidine (TNAZ). The combustion rates of synthesized low-melting explosives of the tetrazine series, as well as other volatiles like TNT, are controlled by reactions in the flame (gas-phase combustion mechanism). It was shown that trinitro and fluorodinitro derivatives most fully meet the requirements for the melt-castable explosives.