The Collaborative International Dictionary of English v.0.48:

Zirconic \Zir*con"ic\, a. (Chem.)
   Pertaining to, containing, or resembling, zirconium; as,
   zirconic oxide; zirconic compounds.
   [1913 Webster]

   Zirconic acid, an acid of zirconium analogous to carbonic
      and silicic acids, known only in its salts.
      [1913 Webster]