Silver sulfide

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Silver sulfide
Ag2S-bas.png
Sulfid stribrny.PNG
Names
IUPAC name
Silver(I) sulfide
Other names
Silver sulfide
Argentous sulfide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.040.384 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 244-438-2
PubChem CID
UNII
  • InChI=1S/2Ag.S/q2*+1;-2 X mark.svgN
    Key: XUARKZBEFFVFRG-UHFFFAOYSA-N X mark.svgN
  • [S-2].[Ag+].[Ag+]
Properties
Ag2S
Molar mass 247.80 g·mol−1
AppearanceGrayish-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]
6.21·10−15 g/L (25 °C)
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]
−32.59 kJ/mol [6]
−40.71 kJ/mol [6]
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
May cause irritation
GHS labelling:
GHS-pictogram-exclam.svg [2]
Warning
H315, H319, H335 [2]
P261, P305+P351+P338 [2]
NFPA 704 (fire diamond)
[7]
NFPA 704.svgHealth 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).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

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%).

Contents

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.

Exceptional ductility of α-Ag2S

Relative to most inorganic materials, α-Ag2S displays exceptional ductility at room temperature. [13] [14] This material can undergo extensive deformation, akin to metals, without fracturing. Such behavior is evident in various mechanical tests; for instance, α-Ag2S can be easily machined into cylindrical or bar shapes and can withstand substantial deformation under compression, three-point bending, and tensile stresses. The material sustains over 50% engineering strain in compression tests and up to 20% or more in bending tests. [13]

The intrinsic ductility of alpha-phase silver sulfide (α-Ag2S) is underpinned by its unique structural and chemical bonding characteristics. At the atomic level, its monoclinic crystal structure, which remains stable up to 451 K, enables the movement of atoms and dislocations along well-defined crystallographic planes known as slip planes. Additionally, the dynamic bonding within the crystal structure supports both the sliding of atomic layers and the maintenance of material integrity during deformation. The interatomic forces within the slip planes are sufficiently strong to prevent the material from cleaving while still allowing for considerable flexibility. [13] Further insights into α-Ag2S's ductility come from density functional theory calculations, which reveal that the primary slip planes align with the [100] direction and slipping occurs along the [001] direction. This arrangement permits atoms to glide over each other under stress through minute adjustments in the interlayer distances, which are energetically favorable as indicated by low slipping energy barriers (ΔEB) and high cleavage energies (ΔEC). These properties ensure significant deformation capability without fracture. Silver and sulfur atoms in α-Ag2S form transient, yet robust interactions that enable the material to retain its integrity while deforming. This behavior is akin to that of metals, where dislocations move with relative ease, providing α-Ag2S with a unique combination of flexibility and strength, making it exceptionally resistant to cracking under mechanical stress. [13]

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. [15]

Silver sulfide is a component of classical qualitative inorganic analysis. [16]

Related Research Articles

<span class="mw-page-title-main">Chalcogen</span> Group of chemical elements

The chalcogens are the chemical elements in group 16 of the periodic table. This group is also known as the oxygen family. Group 16 consists of the elements oxygen (O), sulfur (S), selenium (Se), tellurium (Te), and the radioactive elements polonium (Po) and livermorium (Lv). Often, oxygen is treated separately from the other chalcogens, sometimes even excluded from the scope of the term "chalcogen" altogether, due to its very different chemical behavior from sulfur, selenium, tellurium, and polonium. The word "chalcogen" is derived from a combination of the Greek word khalkόs (χαλκός) principally meaning copper, and the Latinized Greek word genēs, meaning born or produced.

<span class="mw-page-title-main">Ductility</span> Degree to which a material under stress irreversibly deforms before failure

Ductility refers to the ability of a material to sustain significant plastic deformation before fracture. Plastic deformation is the permanent distortion of a material under applied stress, as opposed to elastic deformation, which is reversible upon removing the stress. Ductility is a critical mechanical performance indicator, particularly in applications that require materials to bend, stretch, or deform in other ways without breaking. The extent of ductility can be quantitatively assessed using the percent elongation at break, given by the equation:

<span class="mw-page-title-main">Carbon group</span> Periodic table group

The carbon group is a periodic table group consisting of carbon (C), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), and flerovium (Fl). It lies within the p-block.

<span class="mw-page-title-main">Nonmetal</span> Chemical element that mostly lacks the characteristics of a metal

Nonmetals are chemical elements that mostly lack distinctive metallic properties. They range from colorless gases like hydrogen to shiny crystals like iodine. Physically, they are usually lighter than metals; brittle or crumbly if solid; and often poor conductors of heat and electricity. Chemically, nonmetals have high electronegativity ; and their oxides tend to be acidic.

<span class="mw-page-title-main">Noble metal</span> Metallic elements that are nearly chemically inert

A noble metal is ordinarily regarded as a metallic chemical element that is generally resistant to corrosion and is usually found in nature in its raw form. Gold, platinum, and the other platinum group metals are most often so classified. Silver, copper, and mercury are sometimes included as noble metals, but each of these usually occurs in nature combined with sulfur.

Nickel hydride is either an inorganic compound of the formula NiHx or any of a variety of coordination complexes. It was discovered by Polish chemist Bogdan Baranowski in 1958.

Sulfide (British English also sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. Sulfide also refers to large families of inorganic and organic compounds, e.g. lead sulfide and dimethyl sulfide. Hydrogen sulfide (H2S) and bisulfide (SH−) are the conjugate acids of sulfide.

<span class="mw-page-title-main">Argentite</span>

In mineralogy, argentite (from Latin argentum ' silver') is cubic silver sulfide (Ag2S), which can only exist at temperatures above 173 °C (343 °F), 177 °C (351 °F), or 179 °C (354 °F). When it cools to ordinary temperatures it turns into its monoclinic polymorph, acanthite. The International Mineralogical Association has decided to reject argentite as a proper mineral.

<span class="mw-page-title-main">Zinc sulfide</span> Inorganic compound

Zinc sulfide is an inorganic compound with the chemical formula of ZnS. This is the main form of zinc found in nature, where it mainly occurs as the mineral sphalerite. Although this mineral is usually black because of various impurities, the pure material is white, and it is widely used as a pigment. In its dense synthetic form, zinc sulfide can be transparent, and it is used as a window for visible optics and infrared optics.

<span class="mw-page-title-main">Acanthite</span> Mineral, silver sulfide

Acanthite is a form of silver sulfide with the chemical formula Ag2S. It crystallizes in the monoclinic system and is the stable form of silver sulfide below 173 °C (343 °F). Argentite is the stable form above that temperature. As argentite cools below that temperature its cubic form is distorted to the monoclinic form of acanthite. Below 173 °C acanthite forms directly. Acanthite is the only stable form in normal air temperature.

<span class="mw-page-title-main">Tetrasulfur tetranitride</span> Chemical compound

Tetrasulfur tetranitride is an inorganic compound with the formula S4N4. This vivid orange, opaque crystalline compound is the most important binary sulfur nitride, which are compounds that contain only the elements sulfur and nitrogen. It is a precursor to many S-N compounds and has attracted wide interest for its unusual structure and bonding.

Sulfur compounds are chemical compounds formed the element sulfur (S). Common oxidation states of sulfur range from −2 to +6. Sulfur forms stable compounds with all elements except the noble gases.

<span class="mw-page-title-main">Silver(I) selenide</span> Chemical compound

Silver selenide (Ag2Se) is the reaction product formed when selenium toning analog silver gelatine photo papers in photographic print toning. The selenium toner contains sodium selenite (Na2SeO3) as one of its active ingredients, which is the source of the selenide (Se2−) anion combining with the silver in the toning process.

<span class="mw-page-title-main">Polythiazyl</span> Chemical compound

Polythiazyl, (SN)x, is an electrically conductive, gold- or bronze-colored polymer with metallic luster. It was the first conductive inorganic polymer discovered and was also found to be a superconductor at very low temperatures. It is a fibrous solid, described as "lustrous golden on the faces and dark blue-black", depending on the orientation of the sample. It is air stable and insoluble in all solvents.

Indium(III) sulfide (Indium sesquisulfide, Indium sulfide (2:3), Indium (3+) sulfide) is the inorganic compound with the formula In2S3.

<span class="mw-page-title-main">Aguilarite</span>

Aguilarite is an uncommon sulfosalt mineral with formula Ag4SeS. It was described in 1891 and named for discoverer Ponciano Aguilar.

<span class="mw-page-title-main">Copper(I) sulfide</span> Chemical compound

Copper(I) sulfide is a copper sulfide, a chemical compound of copper and sulfur. It has the chemical compound Cu2S. It is found in nature as the mineral chalcocite. It has a narrow range of stoichiometry ranging from Cu1.997S to Cu2.000S. Samples are typically black.

<span class="mw-page-title-main">Gold(I) sulfide</span> Chemical compound

Gold(I) sulfide is the inorganic compound with the formula Au2S. It is the principal sulfide of gold. It decomposes to gold metal and elemental sulfur, illustrating the "nobility" of gold.

<span class="mw-page-title-main">Gallium(III) sulfide</span> Chemical compound

Gallium(III) sulfide, Ga2S3, is a compound of sulfur and gallium, that is a semiconductor that has applications in electronics and photonics.

<span class="mw-page-title-main">Properties of nonmetals (and metalloids) by group</span>

Nonmetals show more variability in their properties than do metals. Metalloids are included here since they behave predominately as chemically weak nonmetals.

References

  1. 1 2 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. 1 2 3 4 Sigma-Aldrich Co., Silver sulfide. Retrieved on 2014-07-13.
  3. 1 2 3 4 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. 1 2 3 4 5 "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. 1 2 3 4 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. 1 2 3 4 Chen, Lidong (2018). "Room-temperature ductile inorganic semiconductor". Nature Materials. 17: 421–426.
  14. ↑ Chen, Lidong. "Flexible thermoelectrics based on ductile semiconductors". Science. 377 (6608): 854–858.
  15. ↑ "1833 - First Semiconductor Effect is Recorded". Computer History Museum. Retrieved 24 June 2014.
  16. ↑ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN   978-0-08-037941-8.
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