Copper (II) sulfide

Crystal structure
__ Cu 2+      __ S 2−
General
Surname	Copper (II) sulfide
other names	Covellin Cupric sulfide Copper monosulfide
Ratio formula	CuS
Brief description	black solid
External identifiers / databases
CAS number 1317-40-4 EC number 215-271-2 ECHA InfoCard 100,013,884 PubChem 14831 ChemSpider 14145 Wikidata Q416688
properties
Molar mass	95.61 g · mol -1
Physical state	firmly
density	4.6 g cm −3
Melting point	507 ° C (decomposition)
solubility	almost insoluble in water (0.33 mg l −1 , 18 ° C)
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
MAK	0.1 mg m −3
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Copper (II) sulphide is a chemical compound of copper and sulfur . It is a black, brittle solid with the ratio formula CuS. Despite this ratio, the compound not only contains Cu ²⁺ ions, but also consists of a mixture of Cu ⁺ and Cu ²⁺ ions, as well as sulfide ions and disulfide ions . The exact ratio is Cu ₂ ^I Cu ^II (S ₂ ) S.

Occurrence

Copper (II) sulfide occurs naturally as the mineral covellin .

Extraction and presentation

Copper (II) sulfide is produced (in the laboratory) by precipitation from an aqueous solution, for example by introducing hydrogen sulfide .

${\displaystyle \mathrm {Cu_{(aq)}^{2+}+S^{2-}\longrightarrow CuS_{(s)}\downarrow } }$

Highly pure copper (II) sulfide is obtained by reacting a copper (I) sulfide / sulfur mixture at room temperature.

${\displaystyle \mathrm {2\ Cu_{2}S+2\ S\longrightarrow 4\ CuS} }$

properties

Copper (II) sulfide

Physical Properties

Copper (II) sulphide is a black, water-insoluble solid that occurs naturally as sulphidic copper ore. It is electrically conductive. The ore copper (II) sulfide is oxidized to copper sulfate in moist air . The compound is stable in dry air at room temperature. If copper (II) sulfide is heated in the absence of air, it decomposes at 507 ° C to copper (I) sulfide and sulfur. The resulting copper sulfide is not built up stoichiometrically and can be better described by the form Cu _2-x S.

${\displaystyle \mathrm {2\ CuS\longrightarrow Cu_{2}S+S} }$

Roasting the ore in air, on the other hand, leads to copper (II) oxide and sulfur dioxide.

Copper (II) sulfide has a hexagonal crystal structure with the space group P 6 ₃ / mmc (space group number 194) (a = 3.794 Å, c = 16.33 Å) and an enthalpy of formation of −48.5 kJ / mol.

Chemical properties

Copper (II) sulfide is only soluble in concentrated, oxidizing acids . For example, 3 mol CuS react with 8 mol conc. Nitric acid to copper sulfate (3 mol), nitrogen monoxide (8 mol) and water ( redox reaction ). It is insoluble in dilute acids. In the cation separation process , it is therefore already precipitated in the hydrogen sulfide group at pH 4–5 , dissolved in nitric acid and detected as a copper tetrammine complex with ammonia water ( evidence of cations , detection reaction ).

use

Copper (II) sulfide is used for anti-fouling coatings.

In the 1970s and 1980s, copper (II) sulfide was used as a cathode material in lithium batteries for pacemakers .

Individual evidence

1. ↑ ^{a b c d e} Entry on copper (II) sulphide in the GESTIS substance database of the IFA , accessed on December 19, 2019 (JavaScript required)
2. ↑ ^{a b} R. Blachnik, A. Müller: The formation of Cu ₂ S from the elements. I. Copper used in the form of powders . In: Thermochimica Acta . tape 361 , no. 1-2 , October 2000, pp. 31-52 , doi : 10.1016 / S0040-6031 (00) 00545-1 .
3. ^ AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 .
4. ↑ ^{a b c} Georg Brauer (ed.), With the collaboration of Marianne Baudler a . a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume II, Ferdinand Enke, Stuttgart 1978, ISBN 3-432-87813-3 , p. 982.