2-Oxo-1,3,5-trinitro-1,3,5-triazacyclohexane (Keto-RDX or K-6), the most powerful energetic material among nitrourea explosives, has been prepared and scaled up at laboratory level. The identity and purity of the product are tested by elemental analysis, IR, NMR, mass and HPLC techniques. Thermal response and sensitivity experiments on K-6 are also described. The data on sensitivity shows that K-6 can be utilised practically only in phlegmatized form. (C) 2002 Published by Elsevier Science B.V.