The relative orders of impact sensitivity of tetrazole derivatives and their metal salts are investigated by examining the activation energy for forming azide in the process of thermal decomposition based on PM3-SCF-MO calculations. It is found that there is a parallel relationship between the activation energy and the sensitivity and a good linear relationship etween the experimental impact sensitivity of metal salts of tetrazole and the reaction activation energy. It is shown that treating the metal salts of the tetrazole derivatives as the metal derivatives of tetrazole is meaningful. q1999 Elsevier Science B.V. All rights reserved.