TKX-50

The compound is prepared by reacting 5,5′-bistetrazolyl-1,1′-diol (BTO) with hydroxylamine. The starting compound BTO can be obtained relatively easily from glyoxal, hydroxylamine, chlorine, and sodium azide.^{[5] [6]}

Since the initial synthesis of TKX-50 multiple research groups have improved the synthesis to make it more suitable for mass production including by adding protecting groups to make intermediates safer^[7] and the United States Army Research Laboratory by performing multiple steps of the synthesis in a 1-pot reaction.^[8]

TKX-50 is a crystalline solid with no melting point. The compound occurs in two polymorphic crystal forms. At about 180 °C, a second-order phase transition with a small heat capacity change of about 0.3 J Mol⁻¹·K⁻¹is observed, resulting in a transformation from the low-temperature to a high-temperature crystal form. The crystal system changes from monoclinic with the space group P 2 ₁ /c to triclinic with the space group P 1.^[9] The compound is thermally unstable. DSC measurements show an exothermic decomposition reaction above 215 °C with a latent heat of decomposition of −2200 kJ kg ⁻¹ and −520 kJ mol ⁻¹, respectively.^[10][11] The standard enthalpy of formation based on combustion calorimetry measurements is 473 kJ mol⁻¹.^[12]

TKX-50 has been found to lead to melt-cast formulations with higher performance than those with HMX.^[13] Its detonation velocity, Chapman–Jouguet detonation pressure, and density are also superior to RDX.^[1][2]