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And G . Rüdorff'put forward an entirely different view o f the nature o f carbon monofluoride based on X-ray diff'raction studies. T h e proposed structure, shown in Fig. 3, consists o f puckered layers o f carbon atoms, in contrast to the plane layers in graphite itself, the diff'erence being due to the bonding o f each carbon in the sheets to three other carbon THE C A R B O N FLUORIDES •C Fig. 3. 39 oF Crystal lattice of carbon monofluoride, according to W . and G . Riidorfi". [Reproduced by permission Inorganic Chemistry and Radiochemistry, from W .

Sharpj^^^ One of the points that emerges is that tetrafluoroborates have been prepared in several non-aqueous solvents, as is shown by the following examples. Solvent Preparative Reaction HF KHF2 + BF3 ^ BrF3 K F + B2O3 ^ KBF4 IF5 K F + BF3 K F + BF3 ^ KBF4 KBF4 ASF3 KBF4 The nature o f these reactions will be clear from what has been said already about acid-base neutralization reactions in the halogen fluoride systems. In the case o f arsenic trifluoride self-ionization is believed to follow the equation 2 ASF3 ^ ASF2"' + ASF4- The corresponding acid formed by boron trifluoride would then be AsF2"^BF4- which would react with the base K A S F 4 to yield K B F 4 and A S F 3 .

SCF3, FeF3, C 0 F 3 , and PdF3). It will be recalled that aluminum chloride has a layer lattice and that the tribromide has a molecular lattice built up o f Al2Br6 units. Rather similar distinctions exist between the fluorides and other halides of other members o f the group. T h e sharp break between boron and the other elements is apparent from the melting and boiling points o f the trifluorides tabulated below. o" -34° — — 1170° 550° 1257° (sublimes) — — Gallium and indium trifluorides are stable to cold water whereas thallium(III) fluoride is immediately hydrolyzed.