The Collaborative International Dictionary of English v.0.48:

Hydrofluosilicic \Hy`dro*flu`o*si*lic"ic\, a. [Hydro-, 2 +
   fluorine + silicic.] (Chem.)
   Pertaining to, or denoting, a compound consisting of a double
   fluoride of hydrogen and silicon; silicofluoric. See
   Silicofluoric.
   [1913 Webster]