Chemistry:Cobalt sulfide

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Cobalt sulfide
Identifiers
3D model (JSmol)
ChemSpider
EC Number
  • CoS: 215-273-3
RTECS number
  • CoS: GG332500
UNII
Properties
CoxSy
Molar mass 90.9982 g/mol
Appearance black solid (alpha)
grayish-red crystals (beta)
Density 5.45 g/cm3
Melting point 1195 °C
0.00038 g/100 mL (18 °C)
Solubility slightly soluble in acid
+225.0·10−6 cm3/mol
Structure
octahedral (beta)
Hazards
GHS pictograms GHS07: HarmfulGHS09: Environmental hazard
GHS Signal word Warning
HH317Script error: No such module "Preview warning".Category:GHS errors, HH410Script error: No such module "Preview warning".Category:GHS errors
PP261Script error: No such module "Preview warning".Category:GHS errors, PP272Script error: No such module "Preview warning".Category:GHS errors, PP273Script error: No such module "Preview warning".Category:GHS errors, PP280Script error: No such module "Preview warning".Category:GHS errors, PP302+P352Script error: No such module "Preview warning".Category:GHS errors, PP321Script error: No such module "Preview warning".Category:GHS errors, PP333+P317Script error: No such module "Preview warning".Category:GHS errors, PP362+P364Script error: No such module "Preview warning".Category:GHS errors, PP391Script error: No such module "Preview warning".Category:GHS errors, PP501Script error: No such module "Preview warning".Category:GHS errors
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Cobalt sulfide is the name for chemical compounds with a formula CoxSy. Well-characterized species include minerals with the formulas CoS, CoS2, Co3S4, and Co9S8. In general, the sulfides of cobalt are black, semiconducting, insoluble in water, and nonstoichiometric.[2] Cobalt sulfides can be prepared in the laboratory by treating an aqueous solution of cobalt(II) nitrate with hydrogen sulfide according to the following idealized equation:[3]

Co(NO
3
)
2
+ H
2
S → CoS + 2HNO
3

Minerals and hydrometallurgy

Cobalt sulfides occur widely as minerals, comprising major sources of all cobalt compounds. Binary cobalt sulfide minerals include the cattierite (CoS2) and linnaeite (Co3S4). CoS2 (see image in table) is isostructural with iron pyrite, featuring disulfide groups, i.e. Co2+S22−. Linnaeite, also rare, adopts the spinel motif.[4] The Co9S8 compound is known as a very rare cobaltpentlandite (the Co analogue of pentlandite).[5] Mixed metal sulfide minerals include carrollite (CuCo2S4) and siegenite (Co3−xNixS4).

CoS is known as jaipurite. However, this species is questionable.[6][7]

Cobalt sulfide minerals are converted to cobalt via roasting and extraction into aqueous acid. In some processes, cobalt salts are purified by precipitation when aqueous solutions of cobalt(II) ions are treated with hydrogen sulfide. Not only is this reaction useful in the purification of cobalt from its ores, but also in qualitative inorganic analysis.[2]

Applications and research

In combination with molybdenum, the sulfides of cobalt are used as catalysts for the industrial process called hydrodesulfurization, which is implemented on a large scale in refineries. Synthetic cobalt sulfides are widely investigated as electrocatalysts.[8]

References

  1. PubChem. "Cobalt sulfide" (in en). https://pubchem.ncbi.nlm.nih.gov/compound/14832. 
  2. 2.0 2.1 John D. Donaldson, Detmar Beyersmann "Cobalt and Cobalt Compounds" in Ullmann's Encyclopedia of Industrial Chemistry 2005, Wiley-VCH, Weinheim. doi:10.1002/14356007.a07_281.pub2
  3. O. Glemser (1963). "Cobalt Sulfides". in G. Brauer. Handbook of Preparative Inorganic Chemistry, 2nd Ed.. 2. NY, NY: Academic Press. pp. 1523. 
  4. Greenwood, Norman N.; Earnshaw, Alan (1984). Chemistry of the Elements. Oxford: Pergamon Press. ISBN 978-0-08-022057-4. 
  5. "Home". http://www.mindat.org/. 
  6. "Jaipurite". https://www.mindat.org/min-7119.html. 
  7. "List of Minerals". 21 March 2011. https://www.ima-mineralogy.org/Minlist.htm. 
  8. Mathew, Simon; Yella, Aswani; Gao, Peng; Humphry-Baker, Robin; Curchod, Basile F. E.; Ashari-Astani, Negar; Tavernelli, Ivano; Rothlisberger, Ursula et al. (2014). "Dye-sensitized solar cells with 13% efficiency achieved through the molecular engineering of porphyrin sensitizers". Nature Chemistry 6 (3): 242–247. doi:10.1038/nchem.1861. PMID 24557140. Bibcode2014NatCh...6..242M. https://zenodo.org/record/12536. 

Selected literature