The standard molar enthalpy of formation at 298.15 K of S2N+AsF6− by fluorine combustion calorimetry

Abstract The energy of combustion of S 2 N + AsF 6 − in high-pressure fluorine has been measured calorimetrically. The only fluorine-containing gases formed in the combustion were SF 6 and AsF 5 ; both NF 3 and AsF 3 were sought, but not detected. The standard molar enthalpy change for the reaction: S 2 N + AsF 6 − (cr) + ( 11 2 )F 2 (g) = 2SF 6 (g) + ( 1 2 )N 2 (g) + AsF 5 (g) , was −(2265.6±1.5) kJ·mol −1 . From this value was calculated the standard molar enthalpy of formation: Δ f H m o (S 2 N + AsF 6 − , cr, 298.15 K) = −(1413.8±1.9) kJ·mol −1 at p o = 101.325 kPa.