Definition of polythionic acid in English:

polythionic acid

noun

Chemistry
  • Any of a series of unstable acids containing a short chain of sulphur atoms, and having the general formula H₂ Sₙ O₆, where n is 2, 3, 4, or more. Compare "dithionic", "trithionic", "tetrathionic", "pentathionic".

Origin

Mid 19th century; earliest use found in The Chemical Gazette.