Copper sulfide

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Copper sulfide corrosion

Description

Dark blue hexagonal crystals or black powder. Copper sulfide occurs in nature as the blue mineral covellite, that turns black in air. It is used in antifouling paints and in textile dying with aniline black. Copper sulfide was probably used as a black pigment in antiquity (Orna et al 1980). Spots of black copper sulfide can sometimes be seen on corroded bronzes.

Synonyms and Related Terms

covellite (Pigment Blue 34; CI 77450;); cupric sulfide; indigo copper; kopersulfide (Ned.)

Raman

CovelliteRS.jpg


Other Properties

Soluble in nitric acid. Insoluble in water, ethanol, dilute acids, alkalis.

Composition CuS
Mohs Hardness 1.5 - 2.0 (covellite)
Melting Point 220 (dec)
Density 3.9-4.6
Molecular Weight mol. wt. = 95.61

Hazards and Safety

Irritating to skin and eyes. Highly toxic by ingestion. Can emit highly toxic hydrogen sulfide gas it exposed to high heat or acid.

Additional Information

M.V.Orna; M.J.D.Low, N.S.Baer, "Synthetic Blue Pigments: Ninth to Sixteenth Centuries. I. Literature" Studies in Conservation, 25:53-63, 1980.

Additional Images


Sources Checked for Data in Record

  • Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
  • Henry Hodges, Artifacts: An Introduction to Early Materials and Technology, Ronald P. Frye, Kingston, Canada, 1988
  • Monona Rossol, The Artist's Complete Health and Safety Guide, Allworth Press, New York, 1994
  • The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 2724