(chemistry) An anhydride, C₄H₄O₅, of tartaric acid.

(chemistry) hydromellone

(chemistry) An acid known only in its salts (the metatungstates).

(chemistry) An acid obtained by the distillation of terebic acid, and homologous with citraconic acid.

(chemistry) An unstable substance, H₂S₂O₆, known only in its solutions and in certain well-defined salts.

(chemistry) pyroboric acid

(organic chemistry) An organic compound with the chemical formula C₆H₂Cl₂O₄.

(chemistry) A thionic acid, H₂S₃O₆.

propiolic acid

An acid amide derivative of succinic acid.