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 ;
ECHA InfoCard	100.040.384
EC Number	244-438-2;
PubChem CID	166738;
UNII	9ZB10YHC1C ;
CompTox Dashboard (EPA)	DTXSID60925902 DTXSID80893679, DTXSID60925902 ;
	InChI InChI=1S/2Ag.S/q2*+1;-2 Key: XUARKZBEFFVFRG-UHFFFAOYSA-N ;
	SMILES S(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 (S⦵298)	143.93 J/mol·K
Std enthalpy of; formation (ΔfH⦵298)	−32.59 kJ/mol
Gibbs free energy (ΔfG⦵)	−40.71 kJ/mol
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	May cause irritation
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335
Precautionary statements	P261, P305+P351+P338
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 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%).

^ ^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.
^ ^a ^b ^c ^d Sigma-Aldrich Co., Silver sulfide. Retrieved on 2014-07-13.
^ ^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.
^ Comey, Arthur Messinger; Hahn, Dorothy A. (February 1921). A Dictionary of Chemical Solubilities: Inorganic (2nd ed.). New York: The MacMillan Company. p. 835.
^ ^a ^b ^c ^d Cite error: The named reference spring was invoked but never defined (see the help page).
^ ^a ^b ^c ^d Pradyot, Patnaik (2003). Handbook of Inorganic Chemicals. The McGraw-Hill Companies, Inc. p. 845. ISBN 978-0-07-049439-8.
^ "MSDS of Silver Sulfide". saltlakemetals.com. Utah, USA: Salt Lake Metals. Archived from the original on 2014-08-10. Retrieved 2014-07-13.

[crc-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] Sigma-Aldrich Co., Silver sulfide. Retrieved on 2014-07-13.

[hpp-3] 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.

[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.

[spring-5] Cite error: The named reference spring was invoked but never defined (see the help page).

[pphoic-6] 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". saltlakemetals.com. Utah, USA: Salt Lake Metals. Archived from the original on 2014-08-10. Retrieved 2014-07-13.

[1]

[2]

[3]

[4]

[5]

[6]

[7]

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
ECHA InfoCard	100.040.384
EC Number	244-438-2
PubChem CID	166738
UNII	9ZB10YHC1C^N
CompTox Dashboard (EPA)	DTXSID60925902 DTXSID80893679, DTXSID60925902
InChI InChI=1S/2Ag.S/q2*+1;-2^N Key: XUARKZBEFFVFRG-UHFFFAOYSA-N^N
SMILES S(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^⦵₂₉₈)	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
Occupational safety and health (OHS/OSH):
Main hazards	May cause irritation
GHS labelling:
Pictograms	^[2]
Signal word	Warning
Hazard statements	H315, H319, H335^[2]
Precautionary statements	P261, P305+P351+P338^[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