Chemical elements
  Beryllium
    Isotopes
    Energy
    Production
    Application
    Physical Properties
    Chemical Properties
      Beryllium Hydride
      Beryllium Fluoride
      Beryllium Chloride
      Beryllium Bromide
      Beryllium Iodide
      Beryllium Double Halides
      Beryllium Oxyhalides
      Beryllium Oxide
      Beryllium Hydroxide
      Beryllium Beryllate
      Beryllium Peroxide
      Beryllium Sulphide
      Beryllium Sulphide
      Beryllium Double Sulphates
      Beryllium Sulphite
      Beryllium Thiosulphate
      Beryllium Selenate
      Beryllium Chromate
      Beryllium Hydride
      Beryllium Chromite
      Beryllium Molybdate
      Beryllium Nitride
      Beryllium Azide
      Beryllium Nitrate
      Beryllium Phosphates, Phosphite, and Hypophosphite
      Beryllium Hypophosphate
      Beryllium Arsenates
      Beryllium Arsenite
      Beryllium Antimonate
      Beryllium Hydride
      Beryllium Vanadates
      Beryllium Niobate
      Beryllium Carbide
      Beryllium Borocarbide
      Beryllium Carbonate
      Beryllium Acetate
      Beryllium Oxalates
      Beryllium Cyanide
      Beryllium Platinocyanide
      Beryllium Silicates
      Beryllium Silicotungstate
      Beryllium Borate
      Beryllium Aluminate

Beryllium Fluoride, BeF2






Berzelius dissolved beryllium hydroxide in hydrofluoric acid, evaporated to dryness, and dried the residue at 100° C. Lebeau showed that this residue always retained water, and left an oxyfluoride, 5BeF2.2BeO, on heating to redness. This solid oxyfluoride is colourless, almost transparent, soluble in water, and has a density of about 2.01 at 15° C.

The original moist residue is converted into anhydrous beryllium fluoride by heating in a current of hydrogen fluoride. Lebeau also obtained anhydrous beryllium fluoride by igniting the dry double fluoride of ammonium and beryllium, BeF2.2NH4F, in a current of carbon dioxide. It is a vitreous solid, with a density of 2.1 at 15° C. It softens on heating, becomes fluid at about 800° C., finally volatilises, and forms a crystalline sublimate. It is deliquescent, soluble in water in all proportions, slightly soluble in absolute alcohol, converted into an oxyfluoride by oxygen, and readily decomposed by sulphuric acid. Sodium, potassium, lithium, and magnesium, when heated with anhydrous beryllium fluoride, combine with the fluorine and set metallic beryllium free. Hydrofluoric acid does not dissolve it.
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