tetraboric

from The Collaborative International Dictionary of English v.0.48

Pyroboric \Pyr`o*bo"ric\, a. [Pyro- + boric.] (Chem.)
   Pertaining to derived from, or designating, an acid, {H2B4O7}
   (called also {tetraboric} acid), which is the acid ingredient
   of ordinary borax, and is obtained by heating boric acid.
   [1913 Webster]

from The Collaborative International Dictionary of English v.0.48

Tetraboric \Tet`ra*bor"ic\, a. [Tetra- + boric.] (Chem.)
   Same as {Pyroboric}.
   [1913 Webster]