Weak Complexes of Sulfur Compounds with Halide Ligands

Salama B. Salama, Saad Wasif


This review summarizes the study of the formation of SO2 -X- , SOCl2 -X- , SOBr2 -X- , SO2 Cl2 -X-  complexes (X-  = Cl- , Br- , I- , and SCN- ) in pure and mixed solvents of acetonitrile and dimethylsulfoxide over the past 30 years. Spectrometry (290nm-380nm) was the principal technique used for the investigation, since the enthalpies of formation Δ Hfo  of the above complexes are low ( -6.03   -22.51 kJ/mol ). The stability of the complexes depend on the nature of the solvent, acceptor properties of the sulfur compounds, the donor properties of the halide ions and the temperature of the reaction. Also, it was found that the extent of the iodide ion replacement reactions by the other halide depends on the nature of the solvent and the halide ions. SO2 -I-  + X- →  SO2 -X-  + I-  The structures of SO2 -X-  compounds are pyramidal, with X-  at the top of the pyramid, the S atom at the center, and the angle depends on the nature of the halide ion.


science, applied science, basic science

Full Text:



AMIS, E. S. 1965. Effect of Solvent on Reaction Rates, Academic Press, London.

ANDREW, L. J. and KEEFER, R. M. 1961. Molecular complexes of halogens, Adv. Inorg. Chem. Radiochem., 3: 91-131.

ASMUS, E. 1960. Determination of the composition of weak complexes, Z. Analyt. Chem., 178: 104-116.

BASOLO, F. and PEARSON, R. G. 1958. Mechanisms of Inorganic Reactions, Wiley, New York.

BELL, R. P. 1965. The Proton in Chemistry, Methuen, London.

BENESI, H. A. and HILDERBRAND, J. 1949. A spectrophotometric investigation of the interaction of iodine with aromatic hydrocarbons, J. Amer. Chem. Soc., 71: 2703-2707.

BENSON, R. 1960. The Foundations of Chemical Kinetics, McGraw Hill, New York.

BUNCEL, E. and LEUNG, H. W. 1975. Catalysis by tertiary amines of σ- complex formation between 1,3,5 trinitrobenzene and aniline, J. C. S. Chem. Comm : 19-20.

BURKE, T. G. and SMITH, D. F. 1959. HF-SO2 and similar vapor-phase complexes, J. Mol. Spectroscopy 3: 381-385.

BUROW, D. F. 1970. Internal-reflection spectroscopy of non-aqueous solvent systems: Halides in liquid sulfur dioxide, Develop. Appl. Spectrosc., 7B: 111-113.

CHADWICK, D., FROST, D. C., HERRING, F. G. and MCLEAN, R. A. N. 1973. Photoelectron spectra of sulfuryl and thionyl halides, Canad. J. Chem., 51: 1893-1905.

DAY, M. C. and SELBIN, J. 1969. Theoretical Inorganic Chemistry, Reinhold and Winston, New York.

DRAGO, R. S. 1959. Molecular addition compounds of iodine. An absolute method for the spectrophotometric determination of equilibrium constants, J. Amer. Chem. Soc., 81: 6138-6141.

FRIEDMAN, L. and WETTER, W. P. 1967. Purification of thionyl chloride, J. Chem. Soc., (A): 36-37

DOI: http://dx.doi.org/10.24200/squjs.vol5iss0pp31-53


  • There are currently no refbacks.

Copyright (c) 2017 Salama B. Salama, Saad Wasif

Creative Commons License
This work is licensed under a Creative Commons Attribution-NoDerivatives 4.0 International License.


This journal and its content is licensed under a Attribution-NoDerivatives 4.0 International.

Flag Counter