:Roussin's black salt
{{chembox
|Watchedfields = changed
|Name = Roussin's black salt
|ImageFile = RBSalt.png
|ImageClass = skin-invert-image
|ImageSize = 240 px
|OtherNames = potassium heptanitrosyltri-μ3-thiotetraferrate
|Section1={{Chembox Identifiers
|CASNo_Ref = {{cascite|correct|??}}
|CASNo = 12518-87-5
|CASNo_Comment = (potassium salt)
|CASNo1_Ref = {{cascite|changed|??}}
|CASNo1 = 12518-87-5
|CASNo1_Comment = (anion)
|CASNo2_Ref = {{cascite|changed|??}}
|CASNo2 = 54724-04-8
|CASNo2_Comment = (ammonium salt)
|CASNo3_Ref = {{cascite|changed|??}}
|CASNo3 = 83017-31-6
|CASNo3_Comment = (sodium salt)
|PubChem = 119057276
|SMILES = [K+].[Fe-3]12([N+]#[O+])S3[Fe-4]([N+]#[O+])([N+]#[O+])S1[Fe-4]([N+]#[O+])([N+]#[O+])S2[Fe-4]3([N+]#[O+])[N+]#[O+]
|StdInChI=1S/4Fe.K.7NO.3S/c;;;;;7*1-2;;;/q4*-2;8*+1;;;
|StdInChIKey=HCASECMHPPKIPY-UHFFFAOYSA-N
}}
|Section2={{Chembox Properties
|K=1|Fe=4|N=7|O=7|S=3
|Appearance = Black solid
|MeltingPtC = 198 to 200
}}
|Section8={{Chembox Related
|OtherFunction = Roussin's Red Salt
}}
}}
Roussin's black salt is a chemical compound with the formula KFe4S3(NO)7.{{Greenwood&Earnshaw2nd|p=1094}} It consists of the potassium salt of the [Fe4S3(NO)7]− anion, metal nitrosyl compound. First described by Zacharie Roussin in 1858,{{cite journal|last1=Butler|first1=Anthony R.|title=The chemist Z. Roussin (1827-94)|journal=Journal of Chemical Education|date=July 1982|volume=59|issue=7|pages=549|doi=10.1021/ed059p549|bibcode=1982JChEd..59..549B}} it is one of the first synthetic iron-sulfur clusters along with the red salt also bearing his name.
Structure
The cluster anion has the geometry of an incomplete cubane-type cluster with C3v symmetry. The dark colour of the complex is attributed to a number of charge-transfer interactions.{{cite journal|last1=Jaworska|first1=Maria|last2=Stasicka|first2=Zofia|title=Structure and UV–vis spectroscopy of roussin black salt [Fe4S3(NO)7]−|journal=Journal of Molecular Structure|date=March 2006|volume=785|issue=1–3|pages=68–75|doi=10.1016/j.molstruc.2005.09.030|bibcode=2006JMoSt.785...68J}}
image:Roussins black salt from crystallographic coordinates.tif
Synthesis
Roussin’s black salt is produced by the reaction of nitrous acid, potassium hydroxide, potassium sulfide, and iron(II) sulfate in aqueous solution.{{cite journal|last1=Marchlewski|first1=L.|last2=Sachs|first2=J.|title=Studien über ROUSINS Salz|journal=Zeitschrift für anorganische Chemie|date=1892|volume=2|issue=1|pages=175–181|doi=10.1002/zaac.18920020117|url=https://zenodo.org/record/1428068}} It can also be formed by the conversion of Roussin's red salt in mildly acidic conditions. This reaction is reversible and Roussin’s red salt is reformed upon alkalization of the reaction solution.
Uses
Roussin’s black salt is a nitric oxide donor.{{cite journal|last1=Janczyk|first1=Agnieszka|last2=Wolnicka-Glubisz|first2=Agnieszka|last3=Chmura|first3=Antonina|last4=Elas|first4=Martyna|last5=Matuszak|first5=Zenon|last6=Stochel|first6=Grazyna|last7=Urbanska|first7=Krystyna|title=NO-dependent phototoxicity of Roussin's black salt against cancer cells|journal=Nitric Oxide|date=February 2004|volume=10|issue=1|pages=42–50|doi=10.1016/j.niox.2004.01.009|pmid=15050534}} Also, Roussin’s Black Salt exhibits antibacterial activity in some food processing applications.{{Greenwood&Earnshaw2nd|pages=1094–1095}}
See also
References
{{Reflist|2}}
{{Nitric oxide signaling}}