The bond dissociation energies of SO₃—X^– (X = F, Cl, Br, and I)

Abstract

The gas-phase strengths of the SO 3 -X -bonds (X = Cl, Br, and I) have been determined to be 222 ± 13, 179 ± 11, and 161 ± 9 kJ/mol, respectively, by measuring thresholds for collision-induced dissociation in a flowing afterglow-tandem mass spectrometer. An upper limit of D(SO 3 -F -) ≤ 488 ± 19 kJ/mol was also determined. The periodic trends in the halide affinities of SO 3 closely parallel those for SO 2 and other Lewis acids. Bond strengths computed using the B3LYP, MP2, QCISD(T), and other models with several basis sets are generally lower than experiment.Résumé : Utilisant un spectromètre de masse en tandem à écoulement postluminescence, on a mesuré les seuils de dissociation induite par une collision et on en déduit que les forces, en phase gazeuse, des liaisons SO 3 -X -(X = Cl, Br et I) sont respectivement de 222 ± 13, 179 ± 11 et 161 ± 9 kJ/mol. On a aussi déterminé que la limite supérieure de D(SO 3 -F -) est ≤ 488 ± 19 kJ/mol. Les tendances périodiques dans les affinités des halogénures pour le SO 3 sont parallèles à celles pour le SO 2 et pour d'autres acides de Lewis. Les forces des liaisons calculées par les méthodes B3LYP, MP2, QCISD(T) et d'autres modèles en utilisant plusieurs ensembles de bases sont généralement inférieures aux valeurs expérimentales.

Electrospray Mass Spectrometric Detection of Products and Short-Lived Intermediates in Aqueous Aerosol Microdroplets Exposed to a Reactive Gas

“…Curve deconvolution into two sigmoids, followed by the conversion of laboratory (KE) to center-of-mass (CEM) kinetic energies [CEM = m /( m + M ) KE, where m = 28 is the molecular mass of the N 2 collider gas and M = 207, 239, or 381, the molecular masses of the various anions] leads to the fragmentation curves shown in Figure B. Threshold CEM energies are consistent with the reported values for BDE(I - −I 2 ) = 1.31 eV, and BDE(I - −SO 3 ) = 1.67 eV . The fact that IS 2 O 3 - and ISO 3 - have similar stabilities in the gas phase suggests the presence of weak I−S bonds in both species …”

Chemical ionization quadrupole mass spectrometer with an electrical discharge ion source for atmospheric trace gas measurement

“…The formation enthalpy for IO − 3 ( H 298 f (IO − 3 ) = −211 kJ mol −1 ) was calculated from its electron affinity (453.5 kJ mol −1 ; Wen et al, 2011) and the formation enthalpy of IO 3 (242 kJ mol −1 ; Goos et al, 2005). The formation enthalpy for ISO − 3 ( H 298 f (ISO − 3 ) = −752 kJ mol −1 ) was calculated from the SO 3 −I − bond strength (161 kJ mol −1 ; Hao et al, 2005) and the formation enthalpies of I − (−195 kJmol −1 ; Goos et al, 2005) and SO 3 (−396 kJ mol −1 ; Goos et al, 2005). In the absence of thermodynamic data for IO − 4 , we cannot assess the reaction enthalpies for Reactions (R15) and (R17).…”

Chemical ionisation quadrupole mass spectrometer with an electrical discharge ion source for atmospheric trace gas measurement

“…The formation enthalpy for IO3 -(Hf 298 (IO3 -) = -211 kJ mol -1 ) was calculated from its electron affinity (453.5 kJ mol -1 , (Wen et al, 2011) and the formation enthalpy of IO3 (242 kJ mol -1 , (Goos et al, 2005)). The formation enthalpy for ISO3 -(Hf 298 (ISO3 -) = -752 kJ mol -1 ) was calculated from the SO3-Ibond strength (161 kJ mol -1 , (Hao et al, 2005)) and the formation enthalpies of I -(-195 kJmol -1 , (Goos et al, 2005)) and SO3…”