Silver Sulfide

Silver sulfide
Names
	IUPAC name Silver(I) sulfide
	Other names Silver sulfide ; Argentous sulfide
Identifiers
CAS Number	21548-73-2 ;
3D model (JSmol)	Interactive image;
ChemSpider	145878 ;
EC Number	244-438-2;
PubChem CID	166738;
UNII	9ZB10YHC1C ;
	InChI InChI=1S/2Ag.S/q2*+1;-2 Key: XUARKZBEFFVFRG-UHFFFAOYSA-N ;
	SMILES [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); 7.12 g/cm3 (117 °C)
Melting point	836 °C (1,537 °F; 1,109 K)
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
Structure
Crystal structure	Cubic, cI8 (α-form) ; Monoclinic, mP12 (β-form); Cubic, cF12 (γ-form)
Space group	Im3m, No. 229 (α-form); P21/n, No. 14 (β-form); Fm3m, No. 225 (γ-form)
Point group	2/m (α-form); 4/m 3 2/m (β-form, γ-form)
Lattice constant	a = 4.23 Å, b = 6.91 Å, c = 7.87 Å (α-form) α = 90°, β = 99.583°, γ = 90°
Thermochemistry
Heat capacity (C)	76.57 J/mol·K
Std molar; entropy (So298)	143.93 J/mol·K
Std enthalpy of; formation (ΔfH⦵298)	−32.59 kJ/mol
Gibbs free energy (ΔfG˚)	−40.71 kJ/mol
Hazards
Main hazards	May cause irritation
GHS pictograms
GHS Signal word	Warning
GHS hazard statements	H315, H319, H335
GHS precautionary statements	P261, P305+351+338
NFPA 704 (fire diamond)	0 0 0
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
	verify (what is ?)
	Infobox references

Silver sulfide is an inorganic compound with the formula Ag₂S. 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

↑ ^1.0 ^1.1 Lide, David R., ed (2009). CRC Handbook of Chemistry and Physics (90th ed.). Boca Raton, Florida: CRC Press. ISBN 978-1-4200-9084-0.
↑ ^2.0 ^2.1 ^2.2 ^2.3 Sigma-Aldrich Co., Silver sulfide. Retrieved on 2014-07-13.
↑ ^3.0 ^3.1 ^3.2 ^3.3 Tonkov, E. Yu (1992). High Pressure Phase Transformations: A Handbook. 1. Gordon and Breach Science Publishers. p. 13. ISBN 978-2-88124-761-3. https://books.google.com/books?id=uo8wVw9Gq7wC&pg=PA13.
↑ Comey, Arthur Messinger; Hahn, Dorothy A. (February 1921). A Dictionary of Chemical Solubilities: Inorganic (2nd ed.). New York: The MacMillan Company. p. 835. https://archive.org/details/in.ernet.dli.2015.171090.
↑ ^5.0 ^5.1 ^5.2 ^5.3 ^5.4 "Silver sulfide (Ag2S) crystal structure". Non-Tetrahedrally Bonded Elements and Binary Compounds I. Landolt-Börnstein - Group III Condensed Matter. 41C. Springer Berlin Heidelberg. 1998. pp. 1–4. doi:10.1007/10681727_86. ISBN 978-3-540-31360-1. https://link.springer.com/static-content/lookinside/996/chp%3A10.1007%2F10681727_86/000.png.
↑ ^6.0 ^6.1 ^6.2 ^6.3 Pradyot, Patnaik (2003). Handbook of Inorganic Chemicals. The McGraw-Hill Companies, Inc.. p. 845. ISBN 978-0-07-049439-8.
↑ "MSDS of Silver Sulfide". Salt Lake Metals. http://www.saltlakemetals.com/MSDS_Silver_Sulfide.htm.
↑ Zumdahl, Steven S.; DeCoste, Donald J. (2013). Chemical Principles (7th ed.). Cengage Learning. p. 505. ISBN 978-1-111-58065-0. https://books.google.com/books?id=hsuV9JTGaP8C&pg=PA505.
↑ "Degradation of Power Contacts in Industrial Atmosphere: Silver Corrosion and Whiskers". 2002. https://nepp.nasa.gov/whisker/reference/tech_papers/chudnovsky2002-paper-silver-corrosion-whiskers.pdf.
↑ 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. doi:10.1016/j.watres.2010.01.008. ISSN 0043-1354. PMID 20163816. Bibcode: 2010WatRe..44.2563D.
↑ "Control of Hydrogen Sulfide Generation | Water & Wastes Digest" (in en). 5 March 2012. https://www.wwdmag.com/corrosion/control-hydrogen-sulfide-generation.
↑ Frueh, A. J. (1958). The crystallography of silver sulfide, Ag2S. Zeitschrift für Kristallographie-Crystalline Materials, 110(1-6), 136-144.
↑ "1833 - First Semiconductor Effect is Recorded". http://www.computerhistory.org/semiconductor/timeline/1833-first.html.
↑ 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

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Original source: https://en.wikipedia.org/wiki/Silver sulfide. Read more

[crc-1] 1.0 ^1.1 Lide, David R., ed (2009). CRC Handbook of Chemistry and Physics (90th ed.). Boca Raton, Florida: CRC Press. ISBN 978-1-4200-9084-0.

[sigma-2] 2.0 ^2.1 ^2.2 ^2.3 Sigma-Aldrich Co., Silver sulfide. Retrieved on 2014-07-13.

[hpp-3] 3.0 ^3.1 ^3.2 ^3.3 Tonkov, E. Yu (1992). High Pressure Phase Transformations: A Handbook. 1. Gordon and Breach Science Publishers. p. 13. ISBN 978-2-88124-761-3. https://books.google.com/books?id=uo8wVw9Gq7wC&pg=PA13.

[doc00-4] Comey, Arthur Messinger; Hahn, Dorothy A. (February 1921). A Dictionary of Chemical Solubilities: Inorganic (2nd ed.). New York: The MacMillan Company. p. 835. https://archive.org/details/in.ernet.dli.2015.171090.

[spring-5] 5.0 ^5.1 ^5.2 ^5.3 ^5.4 "Silver sulfide (Ag2S) crystal structure". Non-Tetrahedrally Bonded Elements and Binary Compounds I. Landolt-Börnstein - Group III Condensed Matter. 41C. Springer Berlin Heidelberg. 1998. pp. 1–4. doi:10.1007/10681727_86. ISBN 978-3-540-31360-1. https://link.springer.com/static-content/lookinside/996/chp%3A10.1007%2F10681727_86/000.png.

[pphoic-6] 6.0 ^6.1 ^6.2 ^6.3 Pradyot, Patnaik (2003). Handbook of Inorganic Chemicals. The McGraw-Hill Companies, Inc.. p. 845. ISBN 978-0-07-049439-8.

[slm2-7] "MSDS of Silver Sulfide". Salt Lake Metals. http://www.saltlakemetals.com/MSDS_Silver_Sulfide.htm.

[8] Zumdahl, Steven S.; DeCoste, Donald J. (2013). Chemical Principles (7th ed.). Cengage Learning. p. 505. ISBN 978-1-111-58065-0. https://books.google.com/books?id=hsuV9JTGaP8C&pg=PA505.

[9] "Degradation of Power Contacts in Industrial Atmosphere: Silver Corrosion and Whiskers". 2002. https://nepp.nasa.gov/whisker/reference/tech_papers/chudnovsky2002-paper-silver-corrosion-whiskers.pdf.

[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. doi:10.1016/j.watres.2010.01.008. ISSN 0043-1354. PMID 20163816. Bibcode: 2010WatRe..44.2563D.

[11] "Control of Hydrogen Sulfide Generation | Water & Wastes Digest" (in en). 5 March 2012. https://www.wwdmag.com/corrosion/control-hydrogen-sulfide-generation.

[12] Frueh, A. J. (1958). The crystallography of silver sulfide, Ag2S. Zeitschrift für Kristallographie-Crystalline Materials, 110(1-6), 136-144.

[CHM-semicon-13] "1833 - First Semiconductor Effect is Recorded". http://www.computerhistory.org/semiconductor/timeline/1833-first.html.

[14] Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.

Names


IUPAC name Silver(I) sulfide
Other names Silver sulfide Argentous sulfide
Identifiers
CAS Number	21548-73-2^Y
3D model (JSmol)	Interactive image
ChemSpider	145878^N
EC Number	244-438-2
PubChem CID	166738
UNII	9ZB10YHC1C^N
InChI InChI=1S/2Ag.S/q2*+1;-2^N Key: XUARKZBEFFVFRG-UHFFFAOYSA-N^N
SMILES [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 (K_sp)	6.31·10⁻⁵⁰
Solubility	Soluble in aq. HCN, aq. citric acid with KNO₃ Insoluble in acids, alkalies, aqueous ammoniums^[4]
Structure
Crystal structure	Cubic, cI8 (α-form) Monoclinic, mP12 (β-form) Cubic, cF12 (γ-form)^[3]^[5]
Space group	Im3m, No. 229 (α-form)^[5] P2₁/n, No. 14 (β-form) Fm3m, No. 225 (γ-form)^[3]
Point group	2/m (α-form)^[5] 4/m 3 2/m (β-form, γ-form)^[3]
Lattice constant	a = 4.23 Å, b = 6.91 Å, c = 7.87 Å (α-form)^[5] α = 90°, β = 99.583°, γ = 90°
Thermochemistry
Heat capacity (C)	76.57 J/mol·K^[6]
Std molar entropy (S^o₂₉₈)	143.93 J/mol·K^[6]
Std enthalpy of formation (Δ_fH^⦵₂₉₈)	−32.59 kJ/mol^[6]
Gibbs free energy (Δ_fG˚)	−40.71 kJ/mol^[6]
Hazards
Main hazards	May cause irritation
GHS pictograms	^[2]
GHS Signal word	Warning
GHS hazard statements	H315, H319, H335^[2]
GHS precautionary statements	P261, P305+351+338^[2]
NFPA 704 (fire diamond)	^[7] 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 ^YN ?)
Infobox references