Enthalpy of Formation of Gaseous Nitryl Fluoride FNO 2

Contradictory literature data on thermal stability, some methods of synthesis, and thermodynamic characteristics of nitryl fluoride have been considered and analyzed. Reliable estimates of reaction enthalpies have been obtained: 2FNO 2 = 2FNO + O 2 , Δ r H °(0) ≥ 173.5, NO 2 + 2CoF 3 (c) = FNO 2 + Co 2 F 5 (c), Δ r H °(0) = –7.4; 3/2N 2 O 4 + NaF(c) = FNO 2 + NO + NaNO 3 (c), Δ r H °(0) = 11.3 kJ/mol. A new value of the enthalpy of formation of nitryl fluoride Δ f H °(FNO 2 (g), 0) = –161 ± 15 kJ/mol has been recommended. For the interaction of FNO 2 with V 2 O 5 (c) as an example, the impossibility of formation of crystalline vanadium pentafluoride has been demonstrated.