caa a22 4500 469038659 CHVBK 20180323132803.0 cr unu---uuuuu 170328e19920601xx s 000 0 eng 10.1007/BF00816846 doi (NATIONALLICENCE)springer-10.1007/BF00816846 Spectrochemistry of solutions, part 23. Changes of enthalpy and entropy in the formation of contact ion pairs: A vibrational spectroscopic appraisal using thiocyanate and azide solutions [Elektronische Daten] [D. Chingakule, P. Gans, J. Gill, P. Longdon] Spektrochemie von Lösungen, 23. Mitt.: Änderungen von Enthalpie und Entropie bei der Bildung von Kontakt-Ionenpaaren. Eine vibrationsspektroskopische Studie an Thiocyanat- und Azid-Lösungen Summary: The vibrational spectra of solutions have been analyzed to assess both qualitatively and quantitatively the changes in enthalpy and entropy for ion pair formation in solutions of LiNCS, Mg(NCS)2, and LiN3 in liquid ammonia, dimethylformamide, dimethylsulphoxide and acetonitrile. Contrary to predictions both the ΔH ass and ΔS ass terms are all positive in the cases examined, indicating that the driving force in the ion association process derives from solvent-solute restructuring, and not the energy of the interaction between the cation and anion. This characteristic of contact ion pair formation is likely to be found to be applicable over a wide range of solvents. The following specific values of the thermodynamic parameters at 298 K have been obtained: LiNCS/DMF, ΔG=−1.3 (1) kJ mol−1, ΔH ass =+1.8 (5) kJ mol−, ΔS ass =+10 (2) J mol−1 K−1; LiNCS/DMSO, ΔG=+0.9 (2) kJ mol−1, ΔH ass =+0.3 (3) kJ mol−1; Mg(NCS)2/DMF, ΔG ass =−4.0 (3) kJ mol−1, ΔH ass =+15 (4) kJ mol−1, ΔS=+64 (17) kJ mol−1; LiN3/DMSO, ΔG ass =−2.5 (3) kJ mol−1, ΔH ass =+4.9 (9) kJ mol−1, ΔS ass =∼+25 (10) J K−1 mol−1. Springer-Verlag, 1992 Enthalpy nationallicence Entropy nationallicence Vibrational spectra nationallicence Ion pairs nationallicence Electrolyte solutions nationallicence Chingakule D. School of Chemistry, The University, LS2 9JT, Leeds, UK aut Gans P. School of Chemistry, The University, LS2 9JT, Leeds, UK aut Gill J. School of Chemistry, The University, LS2 9JT, Leeds, UK aut Longdon P. School of Chemistry, The University, LS2 9JT, Leeds, UK aut Monatshefte für Chemie / Chemical Monthly Springer-Verlag 123/6-7(1992-06-01), 521-535 0026-9247 123:6-7<521 1992 123 706 https://doi.org/10.1007/BF00816846 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00816846 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Chingakule D. School of Chemistry, The University, LS2 9JT, Leeds, UK aut NATIONALLICENCE 700 1- Gans P. School of Chemistry, The University, LS2 9JT, Leeds, UK aut NATIONALLICENCE 700 1- Gill J. School of Chemistry, The University, LS2 9JT, Leeds, UK aut NATIONALLICENCE 700 1- Longdon P. School of Chemistry, The University, LS2 9JT, Leeds, UK aut NATIONALLICENCE 773 0- Monatshefte für Chemie / Chemical Monthly Springer-Verlag 123/6-7(1992-06-01), 521-535 0026-9247 123:6-7<521 1992 123 706 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer