(chemistry) any compound having the general formula R₃P=O <=> R₃P⁺O⁻

(inorganic chemistry) The compound boron trioxide.

(chemistry) a white, powdered alkali, Li₂O, used in the manufacture of glass and ceramics

(inorganic chemistry) A white, crystalline compound, BeO, used in semiconductors and in specialist ceramic applications.

carbon monoxide / carbon dioxide / carbon suboxide

(inorganic chemistry) nitrous oxide

(chemistry) Any oxide of nitrogen.

(chemistry) the binary compound of nitrogen and oxygen NO; an unstable compound which rapidly oxidizes in the presence of air.

(chemistry) oxygen fluoride

(inorganic chemistry) silicon dioxide (SiO₂), silica. / (inorganic chemistry) silicon monoxide (SiO).