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Copper II Sulfide

Copper ii sulfide or cupric sulfide represented by the chemical formula CuS that bears the IUPAC name sulfanylidenecopper [1] is a black powder or lumps that is soluble in nitric acid but insoluble in water [3]. It occurs as the mineral covellite and is an ionic compound [3, 4]. It is stable in air when it is dry but gets oxidized to copper sulfate by moisture in the air [1].

Copper II Sulfide

Copper II Sulfide Identification

CAS Number 1317-40-4 [1]
PubChem CID 14831 [1]
ChemSpider ID 145403 [2]
EC Number 215-271-2 [1]

Composition and Synthesis

Copper ii sulfide can be prepared by a reaction between molten sulfur and copper that is later followed by boiling in sodium hydroxide [1].

Cu + S = CuS

Copper II Sulfide Formula

Properties and Characteristics of Copper 2 Sulfide

General Properties

Molar mass/molecular weight 95.606 g/mol [1]

Physical Properties

Color/appearance Black powder [3]
Melting point/freezing point 220°C, 428°F (decomposes) [3]
Boiling point N/A [3]
Density 4.6 g ml-1 at 25°C [3]
State of matter at room temperature (normal phase) Solid [3]
Refractive index 1.45 [1]

Chemical Properties

Solubility in water N/A [1]

Atomic Properties

Crystal structure Hexagonal [1]

Copper II Sulfide Structure

Prominent Reactions of CuS

Copper ii sulfide reacts with oxygen at a temperature of 300-500°C to form copper oxide and sulfur dioxide [7].

2CuS + 3O2 = 2CuO + 2SO2

Cupric Sulfide Uses

  1. In the preparation of mixed catalysts [3].
  2. In developing aniline black dye for textile printing [3].
  3. In antifouling paints [3].
  4. In photo optic applications and as a semiconductor [6].

Is It Dangerous

Cupric sulfide is toxic if ingested. Contact with eyes and skin and inhalation should be avoided since it may cause irritation. It has a long lasting harmful effect on aquatic life [1, 3, 5]. Under fire conditions, it decomposes to produce hazardous copper oxides and sulfur oxides [8].


  1. Copper (II) Sulfide –
  2. Copper (II) Sulfide –
  3. Copper (II) Sulfide –
  4. Ionic bond examples –
  5. Copper Sulfide CuS –
  6. Copper Sulfide –
  7. Copper sulfide react with oxygen –
  8. Material Safety Data Sheet –

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