Silver sulfide

An inorganic compound

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Silver sulfide is an inorganic compound with the chemical formula Ag two S， The appearance is grayish black powder. Density 6.85-7.23g/cm three 。 The melting point is 825 ℃. It decomposes at the boiling point. Insoluble in water, soluble in concentrated sulfuric acid and nitric acid , and dissolved in Potassium cyanide and Sodium cyanide Solution. Used for black gold inlay and ceramics. take Sodium sulfide And silver nitrate The solution is prepared by mixing and filtering.

Chinese name: Silver sulfide
Foreign name: silversulfide
Alias: Silver disulfide
chemical formula: Ag two S

molecular weight: two hundred and forty-seven point eight
Melting point: 825 ℃
Water solubility: Insoluble in water
Density: 6.85 to 7.23 g/cm ³
Appearance: Grey black powder

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Material characteristics

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In 1833, the father of electronics Faraday It is found that the resistance of silver sulfide is different from that of metal. As the temperature rises, its resistance decreases, that is Conductivity enhance.

With twin crystal structure:

(1) Grayish black rhombic crystalline silver sulfide. Density 7.326g/cm three 。 175 ℃ is the transition point. Soluble in Potassium cyanide 、 concentrated sulfuric acid 、 nitric acid , insoluble in water.

(2) Black cubic crystalline silver sulfide. Density 7.317g/cm three 。 The melting point is 825 ℃. Soluble in potassium cyanide and acid.^[1]

Numbering system

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CAS No.: 21548-73-2

MDL No.: MFCD00003406

EINECS No. 244-438-2

PubChem No.: 24846574^[1]

toxicology data

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Irritating.^[1]

Ecological data

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Generally speaking, it is harmless to water. If there is no government permission, do not discharge materials into the surrounding environment.^[1]

Calculate chemical data

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1. Reference value for drainage parameter calculation (XlogP): None

2. Number of hydrogen bond donors: 1

3. Number of hydrogen bond receptors: 1

4. Number of rotatable chemical bonds: 0

5. Number of tautomers: none

6. Topological molecular polar surface area 1

7. Number of heavy atoms: 3

8. Surface charge: 0

9. Complexity: 2.8

10. Number of isotope atoms: 0

11. Determine the number of atomic structure centers: 0

12. Number of uncertain atomic structure centers: 0

13. Determine the number of chemical bond structural centers: 0

14. Number of indeterminate chemical bond structure centers: 0

15. Number of covalent bond units: 3^[1]

Properties and stability

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No decomposition if used and stored according to specifications:

Avoid contact with oxides and acids. β-Ag two S is a gray black orthorhombic crystal, which is converted to α - Ag2S at 175 ℃; α-Ag two S is a black cubic crystal. Silver sulfide is extremely insoluble in water; Almost insoluble in dilute Non oxidizing acid ； Insoluble in ammonia water and ammonia salt solution; But soluble in alkali metal cyanide solution and nitric acid; Concentrated H two SO four Can convert Ag two S is converted to silver sulfate and sulfur. Silver sulfide is stable at room temperature and in air, but when heated to more than 350 ℃ in vacuum, filamentous metal silver is formed. If heated directly in air, silver sulfide is easily oxidized to silver sulfate.^[1]

Storage method

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Keep the container sealed. Store in a tight container in a cool, dry place.

synthetic method

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1. At 90~100 ℃, silver oxide (I) reacts with sulfur to form silver sulfide (I). In the presence of moisture, Ag2SO4 can also be converted into silver sulfide (I) by excess sulfur.

2. Set Sodium thiosulfate Silver sulfide (I) can be obtained by reacting with soluble silver salts such as silver oxide (I) and silver nitrate.

3. The soluble silver salt is reacted with soluble sulfide to produce silver sulfide (Ⅰ).^[1]