Nitrogen difluoride
Nitrogen difluoride, also known as difluoroamino, is a reactive radical molecule with formula NF. This small molecule is in equilibrium with its dimer dinitrogen tetrafluoride. As the temperature increases the proportion of NF increases. The molecule is unusual in that it has an odd number of electrons, yet is stable enough to study experimentally. Properties. The energy needed to break the N-N bond in NF is , with an entropy change of 38.6 eu. For comparison, the dissociation energy of the N–N bond is in NO, in NO, and in NH. The enthalpy of formation of NF  (Δ"H") is . At room temperature NF is mostly associated with only 0.7% in the form of NF at pressure. When the temperature rises to 225 °C, it mostly dissociates with 99% in the form of NF. In NF, the N–F bond length is 1.3494 Å and the angle subtended at F–N–F is 103.33°. In the infrared spectrum the N–F bond in NF has a symmetrical stretching frequency of 1075 cm. This compares to 1115 cm in NF, 1021 cm in NF and 998 cm in NF. The microwave spectrum shows numerous lines due to  spin transitions, with or without nuclear spin transitions. The lines form set of two triplets for antisymmetric singlet, or two triplets of triplets for symmetric triplet. Lines appear around 14–15, 24, 25, 26, 27, 28–29, 33, 60, 61, 62, and 65 GHz. The rotational constants for the NF molecule are A = , B = , and C = . The inertial defect Δ = 0.1204 "m"·Å. The centrifugal distortion constants are τ = −7.75, τ = −0.081, τ = 0.30, and τ = −0.13. The dipole moment is 0.13 D (). The ground electronic state of the molecule is B. The gas is  often contaminated with NO or NO. Use. Nitrogen difluoride is formed during the function of a xenon monofluoride excimer laser. Nitrogen trifluoride is the halide carrier gas, which releases fluoride ions when impacted by electrons: The free fluoride ion goes on to react with xenon cations. Nitrogen difluoride can be consumed further to yield nitrogen monofluoride.