Fluoboric acid HBF

Fluoroboric (or Fluoboric) Acid, HBF , mw 87.83 colorless clear, strongly acid liq bp 130° (dec) miscible with w ale. Can be prepd by action of boric + sulfuric acid on fluorspar. Used for prepn of fluoboraces and stabilized diazo sales. Its specially purified so In used in patented process for electrolytic brightening of Al... 

If it is desired to employ fluoboric acid HBF it can be prepared by adding 100 g. of A.R. boric acid in small proportions to 325 g. of A.B. hydrofluoric acid (40 per cent. HF) cooled in ice the hydrofluoric acid is contained in a Bakelite beaker, a beaker coated with wax or in a lead vessel. A simple container may also be prepared by cutting off the neck of the wax bottle (in which the hydrofluoric cusid is supplied) with a large e.g., a butcher s ) knife which has been slightly warmed. One-third of the above solution should be employed in the preparation. Handle with great care. 

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