Structure and thermochemistry of sulfur fluorides SFn (n=1–5) and their ions SF+n (n=1–5)

Abstract

Articles you may be interested inKinetics following addition of sulfur fluorides to a weakly ionized plasma from 300 to 500 K: Rate constants and product determinations for ion-ion mutual neutralization and thermal electron attachment to SF5, SF3, and SF2 J. Chem. Phys. 133, 234304 (2010)

Fragmentation of Energy-Selected SF5CF3+ Probed by Threshold Photoelectron Photoion Coincidence Spectroscopy: Bond Dissociation Energy of SF5-CF3 and Its Atmospheric Implications

“…4 Both our new value for the first DIE of SF 6 , 13.6 ± 0.1 eV, and that derived for the AIE of SF 5 , 9.8 ± 0.2 eV, are in excellent agreement with the results of Fisher et al 4 The AIE result is also in good agreement with two independent Gaussian-2 ab initio calculations. 15,43 All three values are slightly higher that that calculated, 9.52 eV, at the CCSD(T) level of theory. 44 The purpose of these CF 4 in the stratosphere, which has been interpreted to indicate a lifetime of the order of one thousand years.…”

Chapter 3: Trifluoromethyl Sulphur Pentafluoride, SF5CF3: Atmospheric Chemistry and Its Environmental Importance via the Greenhouse Effect

“…Using experimental values for the 0 K enthalpy of formation of CF 3 and SF 5 [40,43], they yield S−C bond strengths of 237 and 245 kJ mol -1 , respectively. It is worth noting that, whilst there has been convergence in recent years between experiment and theory yielding an accepted value for ∆ f H o 0 (CF 3 ), this has not been the case for the SF 5 radical where theory [47] and experiment [43] differ by over 70 kJ mol -1 . Using Irikura's value for ∆ f H o 0 (SF 5 ) [47], for example, Ball [30] predicts a S−C bond strength of 311 kJ mol -1 , much closer to our experimental value of 372 ± 43 kJ mol -1 .…”

“…It is worth noting that, whilst there has been convergence in recent years between experiment and theory yielding an accepted value for ∆ f H o 0 (CF 3 ), this has not been the case for the SF 5 radical where theory [47] and experiment [43] differ by over 70 kJ mol -1 . Using Irikura's value for ∆ f H o 0 (SF 5 ) [47], for example, Ball [30] predicts a S−C bond strength of 311 kJ mol -1 , much closer to our experimental value of 372 ± 43 kJ mol -1 . Xu et al [33], using varying density functional methods but without zero point vibrational energy corrections, obtain dissociation energies for SF 5 CF 3 → SF 5 + CF 3 ranging between 1.9 and 3.1 eV (ca.…”

“…Thus, column 5 of Table 4 also shows values for ∆ r H o 0 calculated using the theoretical values of Irikura [47] for…”

Effects of background gas on sulfur hexafluoride removal by atmospheric dielectric barrier discharge plasma

“…The lowest energy for reaction 4 is about 1.84 eV by forming SF 5 -and F. 14 The lowest direct dissociation energies of SF 6 molecules (reaction 5 and 7) are relatively high as the bond energy of S-F is about 4.60 eV. 22 But the ionization dissociation only happens when the energy is above ∼16 eV, 14 so the probability of this reaction is small considering the electron energy in our plasmas. For SF 6 /H 2 O/background gas mixture plasmas, increasing the input voltage enhance the amount of high energy electrons, thus leading to a higher removal rate.…”