CONDUCTANCE OF SOME HALOBORATE AND BORONIUM SALTS IN ACETONITRILE AT 25 DEGREES

The molar conductances of tetraethylammonium salts of phenyltrichloroborate, tetrabromoborate, and tetraiodoborate and of bis(pyridine)diphenylboronium bromide and boron triiodide-bis(pyridine) in acetonitrile are reported. Tetraethylammonium phenyltrichloroborate and tetraethylammonium tetrabromoborate behave as strong 1:1 electrolytes with no detectable ion-pair association. The ionization mechanism (C2H5)4NBI4(s) = (C2H5)4N+ + BI2(CH3CN)n + + 2I- is proposed to account for the extraordinarily high limiting molar conductance for tetraethylammonium tetraiodoborate. Infrared spectral studies and other conductance data are presented to support this explanation. The molar conductances of bis-(pyridine)diphenylboronium bromide and boron triiodide-bis(pyridine) are typical of strong 1:1 electrolytes. Limiting single-ion conductances are given for (C6H5BCl3-, BBr4-, (C6H5)2B(C5H5N)2+, and BI2(C5H5N)2+. © 1969, American Chemical Society. All rights reserved.