protoxide
/proʊˈtɑkˌsaɪd/
noun
- The first or lowest oxide in a series of oxides of the same element, containing the smallest proportion of oxygen.
- Protoxides are often less stable than higher oxides.
- In chemistry class, we learned that carbon monoxide is a protoxide of carbon.
- The mineral contains a protoxide of iron that gives it a dark color.