- H2S ⇌ HS− + H+
In aqueous solutions, at pH less than 7, hydrogen sulfide is the dominant species; at pH > 7, bisulfide dominates.
A variety of salts are known, including sodium hydrosulfide, potassium hydrosulfide, and ammonium hydrosulfide. 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·(H2O)9, is better described as NaSH·NaOH·(H2O)8.
Aqueous bisulfide absorbs light at around 230nm in the UV/VIS spectrum. Groups have used field spectrometers to measure the absorption due to bisulfide (and hence its concentration) continuously in the ocean and in sewage.
- Goldhaber, M. B.; Kaplan, I. R. (1975), "Apparent Dissociation Constants of Hydrogen Sulfide in Chloride Solutions", Marine Chemistry, 3(1): 83–104
- 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: 3481–3487
- In Press Sutherland-Stacey, L.; Corrie, S.; Neethling, A.; Johnson, I.; Gutierrez; Dexter, R.; Yuan, Z.; Keller, J.; Hamilton, G. (2007), "Continuous Measurement of Dissolved Sulfide in Sewer Systems", Water Science and Technology Text " first5 O. " ignored (help)