- A compound with two oxygen atoms per molecule.
- An oxide containing two atoms of oxygen in each molecule; binoxide.
- An oxide containing but one atom or equivalent of oxygen to two of a metal; a suboxide.
- See Carbonic acid, under <er>Carbonic</er>.
- Any <xref>oxide</xref> containing two <xref>oxygen</xref> <xref>atoms</xref> in each <xref>molecule</xref>.
- an oxide containing two atoms of oxygen in the molecule