The Collaborative International Dictionary of English v.0.48:

Fluosilicic \Flu`o*si*lic"ic\, a. [Fluo- + silicic: cf. F.
   fluosilicique.] (Chem.)
   Composed of, or derived from, silicon and fluorine.
   [1913 Webster]

   Fluosilicic acid, a double fluoride of hydrogen and
      silicon, H2F6Si, obtained in solution in water as a sour
      fuming liquid, and regarded as the type of the
      fluosilicates; -- called also silicofluoric acid, and
      hydrofluosilicic acid.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Silicofluoric \Sil`i*co*flu*or"ic\, a. (Chem.)
   Containing, or composed of, silicon and fluorine; especially,
   denoting the compounds called silicofluorides.
   [1913 Webster]

   Silicofluoric acid (Chem.), a compound of hydrofluoric acid
      and silicon fluoride, known only in watery solution. It is
      produced by the action of silicon fluoride on water, and
      is regarded as an acid, H2SiF6, and the type and origin
      of the silicofluorides.
      [1913 Webster]