Energies and properties of ions involved in electrophilic halogenations: singlet and triplet states of halogen cations (X+, X3+, and X42+) and hydrohalonium ions (HX2+ and H2X+)

Homopolyatomic and heteropolyatomic halogen cations

“…The triatomic cation has a singlet ground state (ES-T = -2.5 kcal/mol; S = singlet, T = triplet). The calculation predicts for the bent ( l o r ) C13+ cation two equal CI-Cl distances of 1.998 A [28]. Earlier reports on calculations o{ the singlet C13+ also predict a CZv geometry (2.010 A, 105.6") [29].…”

“…The valence force constants have been calculated [25]. The geometries and relative energies of the singlet and triplet state of C13+ were studied with ab initio MO calculations at the UHF/6-31G"" level [28]. The triatomic cation has a singlet ground state (ES-T = -2.5 kcal/mol; S = singlet, T = triplet).…”

“…However, they have been theoretically modeled with ab initio MO calculations [28]. The optimized geometry of C l : + is nonplanar and has C2 symmetry, with a ClClClCl torsional angle of 95".…”

“…Although the fluorine cations F+, F2+, F3+, and F : + are nonexistent in the solid state, the geometries and relative energies were studied with ab initio calculations [28]. A quantitative scale for the oxidizer strength of F' and F3+ has recently been developed by Christe and Dixon [32].…”

“…The formation of F+ and its existence (or absence) as a reactive intermediate in the fluorination of highly electronegative compounds have been discussed [33,34]. Both experimental and computational studies have been reported for the energy levels in the gas phase [35-371. For the F,' cation, it is likely that it is also a bent singlet [28]. The optimization of F :…”