The Collaborative International Dictionary of English v.0.48:

Tetrazone \Tet"ra*zone\, n. (Chem.)
   Any one of a certain series of basic compounds containing a
   chain of four nitrogen atoms; for example, ethyl tetrazone,
   (C2H5)2N.N2.N(C2H5)2, a colorless liquid having an odor of
   leeks.
   [1913 Webster] Tetric