Thermodynamic Calculations for Reactions Involving Hydrogen Halide Polymers, Ions, and Lewis Acid Adducts. 2. Polychlorohydrogenate(1−) Anions (HnCln₊₁⁻), Polychlorohydrogen(I) Cations (Hn₊₁Cln⁺), and Hydrogen Chloride Polymers (HCl)n

Semiempirical (MNDO, AM1, and PM3) and ab initio (HF/3-21+G(d,p), BVWN/3-21+G(d,p), MP2/3-21+G(d,p), HF/6-311+G(d,p), BVWN/6-311+G(d,p), and MP2/6-311+G(d,p)) energy minimization and frequency calculations have been carried out on three hydrogen chloride polymers, (HCl) n, n = 2−4 (the semiempirical methods were employed for n = 5 and 6 as well); on four polychlorohydrogenate(1−) anions, H n Cl n +1 -, n = 1−4; and on two polychlorohydrogen(I) cations, H n +1 Cl n +, n = 1 and 2. From the results, Δ G °, Δ H °, and Δ S ° values have been calculated for a number of reactions involving these species. The thermodynamic data are presented for 21 reactions using calculations at the MP2/6-311+G(d,p) level, along with a comparison of Δ G ° values obtained from all nine molecular orbital methods. 1 H NMR shielding data have also been calculated for three species, HCl, HCl 2 -, and H 2 Cl +, using the gauge-independent atomic orbital (GIAO) and the continuous set of gauge transformations (CSGT) methods and density functional techniques with large basis sets.