The bisulfide ion, also called hydrogensulfide or hydrosulfide, is the anion with the formula [HS]− (also commonly written [SH]− by analogy to [OH]−). This species is the conjugate base of hydrogen sulfide and in its turn also dissociates in sulfide:
- H2S → HS− + H+
- HS− → S2− + H+
In aqueous solutions, at pH lower than 7, hydrogen sulfide (H2S) is the dominant species but at pH higher than 7, bisulfide (HS−) dominates. Sulfide (S2−) is an extremely basic group and only dominates in strongly alkaline conditions at elevated pH.
A variety of salts are known, including sodium hydrosulfide and potassium hydrosulfide. Ammonium hydrosulfide, a component of "stink bombs" has not been isolated as a pure solid. Some compounds described as salts of the sulfide dianion contain primarily hydrosulfide. For example, the hydrated form of sodium sulfide, nominally with the formula Na2S · 9 H2O, is better described as NaSH · NaOH · 8 H2O.
Aqueous bisulfide absorbs light at around 230 nm in the UV/VIS spectrum. Research groups have used field spectrometers to measure the absorption due to bisulfide (and hence its concentration) continuously in the ocean and in sewage. Bisulfide is sometimes confused with the disulfide dianion, S22−, or −S–S−.
 Coordination chemistry
 See also
- Goldhaber, M.B.; Kaplan, I.R. (1975), "Apparent dissociation constants of hydrogen sulfide in chloride solutions", Marine Chemistry 3 (1): 83–104, doi:10.1016/0304-4203(75)90016-X
- Johnson, K.S.; Coletti, L.S. (2001), "In situ ultraviolet spectrophotometery for high resolution and long-term monitoring of nitrate, bromide and bisulfide in the ocean.", Deep Sea Research 1 (49): 1291–1305
- Guenther, E.A.; Johnson, K.S.; Coale, K.H. (2001), "Direct ultraviolet spectrophotometric determination of total sulfide and iodide in natural waters", Analytical Chemistry 73 (14): 3481–3487, doi:10.1021/ac0013812, PMID 11476251
- Sutherland-Stacey, L.; Corrie, S.; Neethling, A.; Johnson, I.; Gutierrez, O.; Dexter, R.; Yuan, Z.; Keller, J. et al. (2007), "Continuous measurement of dissolved sulfide in sewer systems", Water Science and Technology
- Peruzzini, M.; de los Rios, I. and Romerosa, A. (2001), "Coordination Chemistry of transition metals with hydrogen chalcogenide and hydrogen chalcogenido ligands", Progress in Inorganic Chemistry, Progress in Inorganic Chemistry 49: 169–543, doi:10.1002/9780470166512.ch3, ISBN 978-0-470-16651-2.