{{short description|Inorganic anion containing one sulfur and one hydrogen atoms}} {{distinguish|Bisulfite|Disulfide}} {{Chembox | Name = | ImageFile = Hydrogen sulfide ion.svg | ImageFile1 = Bisulfide-3D-vdW.png | ImageName = Wireframe structural formula of bisulfide with the explicit hydrogen added | SystematicName = Sulfanide (rarely used, not common) | OtherNames = {{Unbulleted list|hydrosulfide|hydrogenosulfide}} | IUPACName = Hydrosulfide | Section1 = {{Chembox Identifiers | CASNo = 15035-72-0 | CASNo_Ref = | PubChem = 5047209 | ChemSpiderID = 4224877 | ChemSpiderID_Ref = | ChEBI = 29919 | ChEBI_Ref = | ChEMBL = 38703 | ChEMBL_Ref = | Gmelin = 24766 | SMILES = [SH-] | StdInChI = 1S/H2S/h1H2/p-1 | StdInChIKey = RWSOTUBLDIXVET-UHFFFAOYSA-M }} | Section2 = {{Chembox Properties | Formula = {{Chem|HS|−}} | H=1 | S=1 | ConjugateAcid = Hydrogen sulfide | ConjugateBase = Sulfide }} | Section3 = | Section4 = | Section5 = | Section6 = }}
'''Bisulfide''' (or '''bisulphide''' in British English) is an inorganic anion with the chemical formula HS<sup>−</sup> (also written as SH<sup>−</sup>). It contributes no color to bisulfide salts. It often coexists with hydrogen sulfide, which has a distinctive putrid smell. It is a strong base.
It is an important chemical reagent and an industrial chemical, mainly used in paper pulp industry (Kraft process). == Properties == 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 {{chem2|Na2S * 9 H2O}}, is better described as {{chem2|NaSH * NaOH * 8 H2O}}.
Aqueous bisulfide absorbs light at around 230 nm in the UV–visible spectrum.<ref>{{Citation | doi = 10.1016/0304-4203(75)90016-X | last1 = Goldhaber | first1 = M.B. | last2 = Kaplan | first2 = I.R. | title = Apparent dissociation constants of hydrogen sulfide in chloride solutions | journal = Marine Chemistry | volume = 3 | issue = 1 | pages = 83–104 | year = 1975 | bibcode = 1975MarCh...3...83G }}</ref> Using this approach, bisulfide has been detected in the ocean<ref>{{Citation | last1 = Johnson | first1 = K.S. | last2 = Coletti | first2 = L.S. | title = In situ ultraviolet spectrophotometry for high resolution and long-term monitoring of nitrate, bromide and bisulfide in the ocean. | journal = Deep-Sea Research | volume = 49 | pages = 1291–1305 | doi = 10.1016/s0967-0637(02)00020-1 | year = 2001| issue = 7 | bibcode = 2002DSRI...49.1291J }}</ref><ref>{{Citation | last1 = Guenther | first1 = E.A. | last2 = Johnson | first2 = K.S. | last3 = Coale | first3 = K.H. | title = Direct ultraviolet spectrophotometric determination of total sulfide and iodide in natural waters | journal = Analytical Chemistry | volume = 73 | pages = 3481–3487 | year = 2001 | doi = 10.1021/ac0013812 | pmid = 11476251 | issue = 14}}</ref> and in sewage.<ref>{{Citation | last1 = Sutherland-Stacey | first1 = L. | last2 = Corrie| first2 = S. | last3 = Neethling | first3 = A. | last4 = Johnson | first4 = I. | last5 = Gutierrez|first5 =O. | last6 = Dexter | first6 = R. | last7 = Yuan | first7 = Z. | last8 = Keller | first8 = J. | last9 = Hamilton | first9 = G. | title = Continuous measurement of dissolved sulfide in sewer systems | journal = Water Science and Technology | volume = | pages = | doi = | year = 2007}}</ref>
=== Basicity === At physiological pH, hydrogen sulfide is almost fully ionized to bisulfide (HS<sup>−</sup>).<ref name=Pluth>{{cite journal |last1=Pluth |first1=Michael D. |last2=Tonzetich |first2=Zachary J. |title=Hydrosulfide complexes of the transition elements: Diverse roles in bioinorganic, cluster, coordination, and organometallic chemistry |journal=Chemical Society Reviews |date=2020 |volume=49 |issue=12 |pages=4070–4134 |doi=10.1039/C9CS00570F |pmid=32420562 }}</ref> Therefore, in biochemical settings, "hydrogen sulfide" is often used to mean, bisulfide. Hydrosulfide has been identified as the third gasotransmitter along with nitric oxide and carbon monoxide.<ref>J. W. Pavlik, B. C. Noll, A. G. Oliver, C. E. Schulz, W. R. Scheidt, “Hydrosulfide (HS<sup>−</sup>) Coordination in Iron Porphyrinates”, Inorganic Chemistry, 2010, vol. 49(3), 1017-1026.</ref>
It has a p''K''<sub>a</sub> of 6.9:<ref name=Pluth/>
{{NumBlk|:|{{chem2|HS- + H2O}} {{EqmL}} {{H2S}} + {{OH-}}|{{EquationRef|1}}}}
=== Reactions === Upon treatment with an acid, bisulfide converts to hydrogen sulfide. Oxidation of bisulfide gives polysulfides and eventually sulfate. When anstrongly heated, alkali bisulfide salts decompose to produce sulfide salts and hydrogen sulfide. {{chem2|2NaHS → H2S + Na2S}}
When treated with metal salts, bisulfide gives the corresponding sulfide: :{{chem2|2NaHS + M(2+)→ MS + 2 Na+}} (M = Ni(II), Pb(II), Cd(II), etc)
This conversion is the basis of some schemes in qualitative inorganic analysis.
Under specific conditions, SH<sup>−</sup> forms some complexes containing SH ligands. Examples include [Au(SH)<sub>2</sub>]<sup>−</sup> and (C<sub>5</sub>H<sub>5</sub>)<sub>2</sub>Ti(SH)<sub>2</sub>, derived from gold(I) chloride and titanocene dichloride, respectively.<ref>{{Citation |author1=Peruzzini, M. |author2=de los Rios, I. |author3=Romerosa, A. |name-list-style=amp | title = Coordination Chemistry of Transition Metals with Hydrogen Chalcogenide and Hydrogen Chalcogenido Ligands | journal = Progress in Inorganic Chemistry | volume = 49 | pages = 169–543 | year = 2001 | doi =10.1002/9780470166512.ch3 | isbn = 978-0-470-16651-2 }}</ref>
== Safety ==
Bisulfide salts release toxic hydrogen sulfide upon acidification.
== See also ==
* Disulfide * Sulfide * Sulfanyl * Thiol, SH bonded to an organic group
== References == {{Reflist}}
Category:Anions Category:Sulfur ions Category:Acid–base chemistry