(inorganic chemistry) A white solid, of empirical formula B₂O₃; it is an inorganic polymer used in making glass and enamel and for synthesizing other boron compounds.

(inorganic chemistry) A yellow oxide of lead, PbO, used in the manufacture of paints and glass.

(inorganic chemistry) The simple systematic name for water, H₂O.

(chemistry) Any of a class of organic compound formed by addition of an oxygen atom to an amine - R₃N⁺-O⁻, but sometimes written R₃N=O.

(chemistry) An aminoxyl radical.

(organic chemistry) An arene epoxide.

(inorganic chemistry, organic chemistry) The derivative of arsine H₃As=O, or its organic derivatives.

(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