二にチオン酸さんにチオンさんMeanings1noundithionic acidchemistryTechnical term in chemistry. Compare with ジチオン酸 (dithionous acid).See also: ジチオン酸二にチオン酸さんは化か学がく式しき H₂S₂O₆ で表あらわされる。Dithionic acid is represented by the chemical formula H₂S₂O₆.