Chem. [f. TETRA- 2 a + OXIDE.] A binary compound containing four atoms of oxygen; e.g., nitrogen tetroxide, NO4.
1866. Roscoe, Elem. Chem., vii. 63. The same blue body [nitric trioxide] is obtained by adding water to nitric tetroxide and drying the distillate over calcium chloride.
1872. Watts, Dict. Chem., VI. 239. The tetroxide … appears … to be capable of existing in the two polymeric modifications NO2, and N2O4.
