Abstract
Energies of combustion of 2,5-dimercapto-1,3,4-thiadiazole and 2,5-diamino-1,3,4-thiadiazole were determined using oxygen bomb calorimetric method. The standard enthalpies of combustion and formation were calculated for 2,5-dimercapto-1,3,4-thiadiazole: Delta H-c degrees = -1930.1. 3.3 kJ/mole, Delta H-f degrees = 32.6 +/- 3.3 kJ/mole and for 2,5-diamino-1,3,4-thiadiazole: Delta H-c degrees = -1956.5 +/- 3.6 kJ/mole, Delta H-f degrees = 301.2 +/- 3.6 kJ/mole, respectively. The values are given for the studied substances in a crystalline state at the temperature of 298.15 K.