The structure of solutions of gallium(I) chloride in benzene
Abstract
The structure of benzene solutions of Ga[GaCl4] and Ga[Ga2Cl7] has been investigated by 13C and 71Ga NMR, Raman spectroscopy and liquid X-ray scattering (LXS). Assignments of the vibrational spectra are based on a reinvestigation of the liquid Ga–GaCl3 system. The results for the Ga[GaCl4]–C6H6 system are in agreement with the view that an ion pair between Ga+ and GaCl4–, which lowers the symmetry of the GaCl4– ion from Td to C2v or lower, is formed. Spectroscopic effects indicating a complex formation between Ga+ and benzene are weak. The salt Ga[Ga2Cl7] was found to be extremely soluble in benzene ( >50% w/w). The results imply that in such solutions the Ga–Clb–Ga bridge in the Ga2Cl7– ion is bent and the ion pairing between Ga+ and Ga2Cl7– takes place via the bridging chloride ion of the latter ion. Results from LXS show that the GaIII-Clb distance is remarkably long, 2.85 Å(24% longer than in solid K[Ga2Cl7]). For this system, 71Ga and 13C NMR as well as Raman spectroscopic results clearly indicate complex formation between Ga1 and benzene.