The enthalpy of combustion of liquid 1,1 -bis(difluoroamino)heptane was measured in a rotating-bomb calorimeter. The enthalpy of vaporization was estimated. The experimental enthalpy of combustion and the estimated enthalpy of vaporization were used to calculate the following values, in kcal. per mole at 298.15°K ., for this compound: standard enthalpy of formation of the liquid from graphite and gaseous hydrogen, fluorine, and nitrogen, -64.82; standard enthalpy of formation of the gas (estimated), -52.8. The N-F thermochemical bond energy in 1,1-bis-(difluoroamino) heptane was estimated to 67.3 kcal., about the same as the N-F thermochemical bond energy in NF3, N2F4, and 1,2-bis(difluoroamino)-4-methylpentane, but several kilocalories less than the N-F thermochemical bond energy in perfluoropiperidine.