The Bisulfide ion, also called hydrosulfide, is the anion with the formula [HS]⁻ (commonly written [SH]⁻). This species is the conjugate base of hydrogen sulfide:

H₂S ⇌ HS⁻ + H⁺

In aqueous solutions, at pH less than 7, hydrogen sulfide is the dominant species but at pH greater than 7, bisulfide dominates.

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·(H₂O)₉, is better described as NaSH·NaOH·(H₂O)₈.

The UV/VIS spectrum of septic sewage from three different sites. The absorption of bisulfide is observed around 230nm in each case.

Aqueous bisulfide absorbs light at around 230 nm in the UV/VIS spectrum^[1]. Groups have used field spectrometers to measure the absorption due to bisulfide (and hence its concentration) continuously in the ocean^[2][3] and in sewage^[4]. Bisulfide is sometimes confused with the disulfide dianion, S₂²⁻.

[edit] Coordination chemistry

SH⁻ is a soft anionic ligand that forms complexes with most metal ions. Examples include [Au(SH)₂]⁻ and (C₅H₅)₂Ti(SH)₂, derived from gold(I) chloride and titanocene dichloride, respectively.^[5]

[edit] See also

Thiol, SH bonded to an organic group

[edit] References

1. ^ Goldhaber, M. B.; Kaplan, I. R. (1975), "Apparent Dissociation Constants of Hydrogen Sulfide in Chloride Solutions", Marine Chemistry 3(1): 83–104 
2. ^ 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 
3. ^ 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, doi:10.1021/ac0013812 
4. ^ In Press Sutherland-Stacey, L.; Corrie, S.; Neethling, A.; Johnson, I.; Gutierrez; Dexter, R.; Yuan, Z.; Keller, J. et al. (2007), "Continuous Measurement of Dissolved Sulfide in Sewer Systems", Water Science and Technology 
5. ^ 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 49: 169–543. doi:10.1002/9780470166512.ch3.