Gallium chloride adduct

The formation of molecular complexes between aluminum trihalides and pyridine or alkylpyridines has been the subject of systematic studies.35,36 Calorimetric data yield bond dissociation energies D(X3Al—py) of 323, 308 and 264 kJ mol-1 for X = C1, Br and I, respectively, and this same order is found for alkylpyridine adducts, although the A1—N bond is weakened in the case of lutidine by the effects of steric hindrance. For gallium halides the values of D(X3M—py) are smaller 248, 237 and 195 kJ mol-1 for chloride, bromide and iodide adducts, respectively. 

Chloride coordination also seems to be present in the adducts of aluminium chloride and gallium(III) chloride s with acetyl chloride and in compounds of aluminium chloride or titanium(IV) chloride with mesitoyl chloride The corresponding compounds of acetyl chloride may also be considered to be ionic in character at least in solutions of liquid sulphur dioxide i-43 while those of benzoyl chloride are represented by coordination through the oxygen atom of the solvent, as has been shown for ClsSbOCClCeHs both by i.r.-measurements and an X-ray analysis . 

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