dioxide
Chemistry term used as a noun or prefix to indicate a compound with two oxygen atoms, e.g., 二酸化炭素 (carbon dioxide).
Carbon dioxide is one of the greenhouse gases.
Sulfur dioxide is contained in volcanic gases.
Means 'oxidation' or 'oxide' in general; 二酸化 specifies two oxygen atoms.
carbon dioxide; CO2
lead dioxide; lead(IV) oxide
chlorine dioxide
sulfur dioxide; sulphur dioxide
nitrogen dioxide
Compound of 二 (two) + 酸化 (oxidation), literally 'two-oxidation', a straightforward chemical naming pattern.
manganese dioxide (MnO2)
carbon dioxide fixation
carbon emission right; right to emit carbon dioxide