Silver sulfide

Silver sulfide
Ball-and-stick model of silver sulfide
Sample of silver sulfide
Names
IUPAC name
Silver(I) sulfide
Other names
Silver sulfide
Argentous sulfide
Identifiers
CAS Number
  • 21548-73-2 checkY
3D model (JSmol)
  • Interactive image
ChemSpider
  • 145878 ☒N
ECHA InfoCard 100.040.384 Edit this at Wikidata
EC Number
  • 244-438-2
PubChem CID
  • 166738
UNII
  • 9ZB10YHC1C ☒N
CompTox Dashboard (EPA)
  • DTXSID60925902 DTXSID80893679, DTXSID60925902 Edit this at Wikidata
InChI
  • InChI=1S/2Ag.S/q2*+1;-2 ☒N
    Key: XUARKZBEFFVFRG-UHFFFAOYSA-N ☒N
  • [S-2].[Ag+].[Ag+]
Properties
Chemical formula
 Ag2S
Molar mass 247.80 g·mol−1
Appearance Grayish-blackish crystal
Odor Odorless
Density 7.234 g/cm3 (25 °C)[1][2]
7.12 g/cm3 (117 °C)[3]
Melting point 836 °C (1,537 °F; 1,109 K)[1]
Solubility in water
 6.21·10−15 g/L (25 °C)
Solubility product (Ksp)
6.31·10−50
Solubility Soluble in aq. HCN, aq. citric acid with KNO3
Insoluble in acids, alkalies, aqueous ammoniums[4]
Structure
Cubic, cI8 (α-form)
Monoclinic, mP12 (β-form)
Cubic, cF12 (γ-form)[3][5]
Im3m, No. 229 (α-form)[5]
P21/n, No. 14 (β-form)
Fm3m, No. 225 (γ-form)[3]
2/m (α-form)[5]
4/m 3 2/m (β-form, γ-form)[3]
a = 4.23 Å, b = 6.91 Å, c = 7.87 Å (α-form)[5]
α = 90°, β = 99.583°, γ = 90°
Thermochemistry
76.57 J/mol·K[6]
Std molar
entropy (S⦵298)
 143.93 J/mol·K[6]
Std enthalpy of
formation (ΔfH⦵298)
 −32.59 kJ/mol[6]
−40.71 kJ/mol[6]
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 May cause irritation
GHS labelling:
GHS07: Exclamation mark[2]
Warning
H315, H319, H335[2]
P261, P305+P351+P338[2]
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 0: Exposure under fire conditions would offer no hazard beyond that of ordinary combustible material. E.g. sodium chlorideFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
0
0
0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)
Infobox references
Chemical compound

Silver sulfide is an inorganic compound with the formula Ag
2S. A dense black solid, it is the only sulfide of silver. It is useful as a photosensitizer in photography. It constitutes the tarnish that forms over time on silverware and other silver objects. Silver sulfide is insoluble in most solvents, but is degraded by strong acids. Silver sulfide is a network solid made up of silver (electronegativity of 1.98) and sulfur (electronegativity of 2.58) where the bonds have low ionic character (approximately 10%).

Formation

Silver sulfide naturally occurs as the tarnish on silverware. When combined with silver, hydrogen sulfide gas creates a layer of black silver sulfide patina on the silver, protecting the inner silver from further conversion to silver sulfide.[8] Silver whiskers can form when silver sulfide forms on the surface of silver electrical contacts operating in an atmosphere rich in hydrogen sulfide and high humidity.[9] Such atmospheres can exist in sewage treatment and paper mills.[10][11]

Structure and properties

Three forms are known: monoclinic acanthite (β-form), stable below 179 °C, body centered cubic so-called argentite (α-form), stable above 180 °C, and a high temperature face-centred cubic (γ-form) stable above 586 °C.[5] The higher temperature forms are electrical conductors. It is found in nature as relatively low temperature mineral acanthite. Acanthite is an important ore of silver. The acanthite, monoclinic, form features two kinds of silver centers, one with two and the other with three near neighbour sulfur atoms.[12] Argentite refers to a cubic form, which, due to instability in "normal" temperatures, is found in form of the pseudomorphosis of acanthite after argentite.

History

In 1833 Michael Faraday noticed that the resistance of silver sulfide decreased dramatically as temperature increased. This constituted the first report of a semiconducting material.[13]

Silver sulfide is a component of classical qualitative inorganic analysis.[14]

References

  1. ^ a b Lide, David R., ed. (2009). CRC Handbook of Chemistry and Physics (90th ed.). Boca Raton, Florida: CRC Press. ISBN 978-1-4200-9084-0.
  2. ^ a b c d Sigma-Aldrich Co., Silver sulfide. Retrieved on 2014-07-13.
  3. ^ a b c d Tonkov, E. Yu (1992). High Pressure Phase Transformations: A Handbook. Vol. 1. Gordon and Breach Science Publishers. p. 13. ISBN 978-2-88124-761-3.
  4. ^ Comey, Arthur Messinger; Hahn, Dorothy A. (February 1921). A Dictionary of Chemical Solubilities: Inorganic (2nd ed.). New York: The MacMillan Company. p. 835.
  5. ^ a b c d e "Silver sulfide (Ag2S) crystal structure". Non-Tetrahedrally Bonded Elements and Binary Compounds I. Landolt-Börnstein - Group III Condensed Matter. Vol. 41C. Springer Berlin Heidelberg. 1998. pp. 1–4. doi:10.1007/10681727_86. ISBN 978-3-540-31360-1.
  6. ^ a b c d Pradyot, Patnaik (2003). Handbook of Inorganic Chemicals. The McGraw-Hill Companies, Inc. p. 845. ISBN 978-0-07-049439-8.
  7. ^ "MSDS of Silver Sulfide". saltlakemetals.com. Utah, USA: Salt Lake Metals. Archived from the original on 2014-08-10. Retrieved 2014-07-13.
  8. ^ Zumdahl, Steven S.; DeCoste, Donald J. (2013). Chemical Principles (7th ed.). Cengage Learning. p. 505. ISBN 978-1-111-58065-0.
  9. ^ "Degradation of Power Contacts in Industrial Atmosphere: Silver Corrosion and Whiskers" (PDF). 2002.
  10. ^ Dutta, Paritam K.; Rabaey, Korneel; Yuan, Zhiguo; Rozendal, René A.; Keller, Jürg (2010). "Electrochemical sulfide removal and recovery from paper mill anaerobic treatment effluent". Water Research. 44 (8): 2563–2571. Bibcode:2010WatRe..44.2563D. doi:10.1016/j.watres.2010.01.008. ISSN 0043-1354. PMID 20163816.
  11. ^ "Control of Hydrogen Sulfide Generation | Water & Wastes Digest". www.wwdmag.com. 5 March 2012. Retrieved 2018-07-05.
  12. ^ Frueh, A. J. (1958). The crystallography of silver sulfide, Ag2S. Zeitschrift für Kristallographie-Crystalline Materials, 110(1-6), 136-144.
  13. ^ "1833 - First Semiconductor Effect is Recorded". Computer History Museum. Retrieved 24 June 2014.
  14. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.

External links

  • Tarnishing of Silver: A Short Review V&A Conservation Journal
  • Images of silver whiskers NASA
Wikimedia Commons has media related to Silver sulfide.
  • v
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Silver(0,I)
  • Ag2F
Silver(I)
  • AgBF4
  • AgBr
  • AgBrO3
  • AgCN
  • AgCNO
  • AgCl
  • AgClO
  • AgClO2
  • AgClO3
  • AgClO4
  • AgF
  • AgI
  • AgIO3
  • AgMnO4
  • AgNO2
  • AgNO3
  • AgN3
  • Ag3N
  • AgReO4
  • AgOCN
  • AgSCN
  • AgCF3SO3
  • AgPF6
  • Ag2CO3
  • Ag2C2
  • Ag2C2O4
  • Ag2CrO4
  • Ag2Cr2O7
  • Ag2MoO4
  • Ag2O
  • Ag2S
  • Ag2SO3
  • Ag2S2O3
  • Ag2SO4
  • AgHSO4
  • Ag2Se
  • Ag2SeO3
  • Ag2Te
  • Ag3AsO4
  • Ag3PO4
  • KAg(CN)2
  • RbAg4I5
  • Ag(NH3)2OH
  • Ag2N2O2
  • Ag2WO4
Organosilver(I) compounds
  • AgC2H3O2
  • AgC22H43O2
  • CH3CH(OH)COOAg
  • C
    18    H
    36    AgO
    2
  • AgC4H3N2NSO2C6H4NH2
  • AgC
    11    H
    23    COO
    • Silver(II)
    • AgF2
    • [Ag(C5H5N)4]S2O8
    Silver(III)
    • Ag2O3
    • AgF3
    • Ag2S3
    Silver(I,III)
    • Ag4O4
    • v
    • t
    • e
    Sulfides (S2−)
    H2S He
    Li2S BeS B2S3
    +BO3     		CS2
    COS     		(NH4)SH O F Ne
    Na2S MgS Al2S3 SiS
    SiS2
    -Si     		PxSy
    -P     		-S2−
    2         		Cl Ar
    K2S CaS ScS
    Sc2S3     		TiS
    TiS2
    Ti2S3
    TiS3     		VS
    VS2
    V2S3     		CrS
    Cr2S3     		MnS
    MnS2     		FeS
    Fe3S4     		CoS NiS Cu2S
    CuS     		ZnS GaS
    Ga2S3     		GeS
    GeS2
    -Ge     		As2S3
    As4S3
    -As     		SeS2
    +Se     		Br Kr
    Rb2S SrS Y2S3 ZrS2 NbS2 MoS2
    MoS3     		Tc Ru Rh2S3 PdS Ag2S CdS In2S3 SnS
    SnS2
    -Sn     		Sb2S3
    Sb2S5
    -Sb     		TeS2 I Xe
    Cs2S BaS * LuS
    Lu2S3     		HfS2 TaS2 WS2
    WS3     		ReS2
    Re2S7     		OsS
    4         		Ir2S3
    IrS2     		PtS
    PtS2     		Au2S
    Au2S3     		HgS Tl2S PbS
    PbS2     		Bi2S3 PoS At Rn
    Fr Ra ** Lr Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og
     
    * LaS
    La2S3     		CeS
    Ce2S3     		PrS
    Pr2S3     		NdS
    Nd2S3     		Pm2S3 SmS
    Sm2S3     		EuS
    Eu2S3     		GdS
    Gd2S3     		TbS
    Tb2S3     		DyS
    Dy2S3     		HoS
    Ho2S3     		ErS
    Er2S3     		TmS
    Tm2S3     		YbS
    Yb2S3
    ** Ac2S3 ThS2 Pa US
    US2     		Np Pu Am Cm Bk Cf Es Fm Md No
    Authority control databases: National Edit this at Wikidata
    • Germany