The hydrogen halides as nonaqueous solvents

The great synthetic value of liquid NH3 as a nonaqueous solvent (p. 424) has encouraged the extensive study of the other neighbour of H2O in the periodic table, namely, hF. Early studies were hampered by the aggressive nature of anhydrous HF towards glass and quartz. 

Hyman and J. J. Katz, Chap. 2 in T. C. Wadding-ton (ed.), Nonaqueous Solvent Systems, pp. 47-81, Academic Press. London, 1965. 

O Donnell, Chap. 25 in Comprehensive Inorganic Chemistry, Vol. 2, pp. 1009-106, Pergamon Press, Oxford, 1973. 

Many of the ionic fiuorides of M, M and M dissolve to give highly conducting solutions due to ready dissociation. Some typical values of the solubility of fiuorides in HF are in Table 17.11 the data show the expected trend towards greater solubility with increase in ionic radius within the alkali metals and alkaline earth metals, and the expected decrease in solubility with increase in ionic charge so that MF MF2 MF3. This is dramatically illustrated by AgF which is 155 times more soluble than AgF2 and TIF which is over 7000 times more soluble than TIF3. 

Consistent with this, the F nmr spectra of solutions at 0° showed the presence of HSO3F, and separate cryoscopic experiments with pure H2SO4 as the sole solute gave a value of u close to unity. 

Early studies were hampered by the aggressive nature of anhydrous HF towards glass and quartz. 

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