Silver thiocyanate
{{chembox
|Name = Silver thiocyanate
|ImageFile = AgSCN-skel.svg
|ImageSize = 160px
|ImageName = Skeletal formula of silver thiocyanate
|ImageFile1 = AgSCN-bas.png
|ImageSize1 = 200px
|ImageName1 = Ball-and-stick model of silver thiocyanate
|IUPACName = Silver(I) thiocyanate, Silver thiocyanate
|OtherNames = Thiocyanic acid, silver (1+) thiocyanate; Silver isothiocyanate; Silver sulphocyanide
|Section1 = {{Chembox Identifiers
|CASNo = 1701-93-5
|CASNo_Ref = {{cascite|correct|CAS}}
|ChemSpiderID = 66941
|ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
|PubChem = 74345
|UNII = S44O8TME5U
|UNII_Ref = {{fdacite|correct|FDA}}
|StdInChI = 1S/CHNS.Ag/c2-1-3;/h3H;/q;+1/p-1
|StdInChI_Ref = {{stdinchicite|correct|inchi}}
|StdInChIKey = RHUVFRWZKMEWNS-UHFFFAOYSA-M
|StdInChIKey_Ref = {{stdinchicite|correct|inchi}}
|SMILES = C(#N)[S-].[Ag+]
|EINECS = 216-934-9
|UNNumber = 3077
}}
|Section2 = {{Chembox Properties
|Formula = AgSCN
|Appearance = Colorless crystals
|Odor = Odorless
|Solubility = 0.14 mg/L (19.96 °C)
0.25 mg/L (21 °C)
6.68 mg/L (100 °C){{cite book|title = A Dictionary of Chemical Solubilities: Inorganic|url = https://archive.org/details/in.ernet.dli.2015.163725|edition = 2nd|first1 = Arthur Messinger|last1 = Comey|first2 = Dorothy A.|last2 = Hahn|place = New York|publisher = The MacMillan Company|date=February 1921|page = 884}}
|SolubilityProduct = 1.03·10−12
|Solubility1 = 43.2 mg/L (25.2 °C, 3 nAgNO3/H2O)
|Solvent1 = silver nitrate
|Solubility2 = 14 mg/kg (0 °C){{cite web|last = Anatolievich|first = Kiper Ruslan|website=chemister.ru|url = http://chemister.ru/Database/properties-en.php?dbid=1&id=8656|title = silver thiocyanate|accessdate = 2014-07-19}}
|Solvent2 = sulfur dioxide
|Solvent3 = methanol
|SolubleOther = Insoluble in acids (reacts) except when concentrated, acetates, aq. nitrates
|MeltingPtC = 170
|MagSus = −6.18·10−5 cm3/mol{{cite book |doi=10.1201/b17118 |title=CRC Handbook of Chemistry and Physics |date=2014 |isbn=978-0-429-17019-5 |editor-last1=Haynes |editor-first1=William M. }}{{pn|date=January 2025}}
}}
|Section3 = {{Chembox Structure
|CrystalStruct = Monoclinic, mS32 (293 K){{cite journal |last1=Zhu |first1=H.-L. |last2=Liu |first2=G.-F. |last3=Meng |first3=F.-J. |title=Refinement of the crystal structure of silver (I) thiocyanate, AgSCN |journal=Zeitschrift für Kristallographie - New Crystal Structures |date=December 2003 |volume=218 |issue=JG |pages=285–286 |doi=10.1524/ncrs.2003.218.jg.285 |doi-access=free }}
|SpaceGroup = C2/c, No. 15 (293 K)
|LattConst_a = 8.792(5) Å
|LattConst_b = 7.998(5) Å
|LattConst_c = 8.207(5) Å (293 K)
|LattConst_beta = 93.75(1)
|UnitCellFormulas = 8
}}
|Section4 = {{Chembox Thermochemistry
}}
|Section5 = {{Chembox Hazards
|GHSPictograms = {{GHS07}}{{GHS09}}{{Sigma-Aldrich|id = 299669|name = Silver thiocyanate|accessdate = 2014-07-19}}
|GHSSignalWord = Warning
|HPhrases = {{H-phrases|302|312|332|410}}
|PPhrases = {{P-phrases|273|280|501}}
|NFPA-H = 2
|NFPA-F = 0
|NFPA-R = 0
}}
}}
Silver thiocyanate is the silver salt of thiocyanic acid with the formula AgSCN. Silver thiocyanate appears as a white crystalline powder. It is very commonly used in the synthesis of silver nanoparticles. Additionally, studies have found silver nanoparticles to be present in saliva present during the entire digestive process of silver nitrate. Silver thiocyanate is slightly soluble in water, with a solubility of 1.68 x 10−4 g/L.{{cite journal |last1=Kästner |first1=Claudia |last2=Lampen |first2=Alfonso |last3=Thünemann |first3=Andreas F. |title=What happens to the silver ions? – Silver thiocyanate nanoparticle formation in an artificial digestion |journal=Nanoscale |date=2018 |volume=10 |issue=8 |pages=3650–3653 |doi=10.1039/C7NR08851E |doi-access=free |pmid=29431819 }} It is insoluble in ethanol, acetone, and acid.{{Cite web |title=SILVER THIOCYANATE {{!}} 1701-93-5 |url=https://www.chemicalbook.com/ChemicalProductProperty_EN_CB8348652.htm |access-date=2023-11-20 |website=ChemicalBook |language=en}}
Structure
AgSCN is monoclinic with 8 molecules per unit cell. Each SCN− group has an almost linear molecular geometry, with bond angle 179.6(5)°. Weak Ag—Ag interactions of length 0.3249(2) nm to 0.3338(2) nm are present in the structure.
Production
= Solution reaction =
Silver thiocyanate has been commonly produced by the reaction between silver nitrate and potassium thiocyanate.{{fact|date=January 2025}}
:{{chem2 | AgNO3 + KSCN -> KNO3 + AgSCN }}
= Ion-exchange route =
Silver thiocyanate may be formed via an ion exchange reaction. In this double displacement reaction, silver nitrate and ammonium thiocyanate are dissolved in distilled water to produce silver thiocyanate and ammonium nitrate.{{cite journal |last1=Zhang |first1=Shuna |last2=Zhang |first2=Shujuan |last3=Song |first3=Limin |last4=Wu |first4=Xiaoqing |last5=Fang |first5=Sheng |title=Synthesis and photocatalytic property of a new silver thiocyanate semiconductor |journal=Chemical Engineering Journal |date=May 2014 |volume=243 |pages=24–30 |doi=10.1016/j.cej.2014.01.015 |bibcode=2014ChEnJ.243...24Z }}
:{{chem2 | AgNO3 + NH4SCN -> NH4NO3 + AgSCN }}
Additionally, silver thiocyanate can be formed through the double displacement reaction between ammonium thiocyanate and silver chloride to form a precipitate of silver thiocyanate.
:{{chem2 | AgCl + NH4SCN -> NH4Cl + AgSCN }}
Uses
The most common use of silver thiocyanate is as a silver nanoparticle. Silver thiocyanate nanoparticles have been found in saliva throughout the entire artificial digestion of silver nitrate.{{cite journal |last1=Kästner |first1=Claudia |last2=Lampen |first2=Alfonso |last3=Thünemann |first3=Andreas F. |title=What happens to the silver ions? – Silver thiocyanate nanoparticle formation in an artificial digestion |journal=Nanoscale |date=2018 |volume=10 |issue=8 |pages=3650–3653 |doi=10.1039/c7nr08851e |pmid=29431819 |doi-access=free }} The nanoparticles can also be used as good ion conductors.{{cite journal |last1=Yang |first1=Ming |last2=Ma |first2=Jing |title=Synthesis and characterizations of AgSCN nanospheres using AgCl as the precursor |journal=Applied Surface Science |date=September 2009 |volume=255 |issue=23 |pages=9323–9326 |doi=10.1016/j.apsusc.2009.07.028 |bibcode=2009ApSS..255.9323Y }}
Silver thiocyanate has also been used to absorb uv-visible light at values less than 500 nm. At longer wavelengths, silver thiocyanate has been found to have good photocatalytic properties.
Characterization
Upon production, silver thiocyanate can be characterized through a wide range of techniques: x-ray powder diffraction (XRD), x-ray photoelectron spectroscopy (XPS), Raman Spectroscopy, ultraviolet photoelectron spectroscopy (UPS), and thermogravimetric analysis (TGA).{{cn|date=August 2024}}