Chromic oxide

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Chromic oxide

Description

A dull, olive-green color pigment that occurs naturally as the mineral eskolaite. A process for synthetically producing anhydrous, opaque chrome oxide green was developed in 1809 by Vauquelin. The colorant was listed as an artists pigment in the 1840 Winsor and Newton catalog (Newman 1997). It is opaque, lightfast, and durable with excellent resistance to chemicals and heat. Chromic oxide has limited use in paints because of its dull color. However, it absorbs infrared radiation well and this has led to its use in deck paints and camouflage coatings for military purposed. Chromium oxide is also used as an abrasive, as a glaze color, and for tanning leather.

Chromic oxide
Chromium oxide green

Synonyms and Related Terms

chromium (III) oxide; chrome oxide; opaque chromium oxide; Pigment Green 17; CI 77288; eskolaite (mineral); óxido de cromo (Esp.); Chromoxidgrün (Deut.); Chromoxid (Deut.); kromivihreä (Fin.); oxyde de chrome (Fr.); vert d'oxyde chrome (Fr.); ossido di cromo (It.); chroomoxidegroen (Ned.); kromoxidgrønn (Nor.); óxido de crómio (Port.); chromium oxide green opaque; chrome sesquioxide; Anadonis green; Schnitzer's green; Reading green; Dingler's green; ultramarine green; leaf green; oil green; green rouge; chromia; ancanthus green --not to be confused with chrome green (lead chromate and Prussian blue) and emerald green (copper acetoarsenite); Schnitzer's green

Raman

Chromeoxideopaque531.jpg

FTIR

Chromicoxide5m.jpg

FTIR

Chromicoxide5m.jpg

XRD

PIG402.jpg

Risks

  • Toxic by ingestion, inhalation and skin contact.
  • Suspected carcinogen.
  • Non-flammable
  • ThermoFisher: SDS

Physical and Chemical Properties

  • Particle size 0.1 - 1.0 micrometers.
  • Anisotropic.
  • Resistant to acids and alkalis.
  • Hexagonal crystal system.
  • Pleochroism from emerald to olive green.
Composition Cr2O3
CAS 1308-38-9
Melting Point 2241-2291 C
Density 5.10-5.21 g/ml
Molecular Weight mol. wt.=151.99
Refractive Index 2.5
Boiling Point 4000 C

Comparisons

Properties of Common Abrasives

Resources and Citations

  • R. Newman, "Chromium Oxide Greens", Artists Pigments, Volume 3, E. West FitzHugh (ed.), Oxford University Press: Oxford, 1997.
  • Web Minerals: Eskolaite
  • R. J. Gettens, G.L. Stout, Painting Materials, A Short Encyclopaedia, Dover Publications, New York, 1966 Comment: dens=5.10, ref index=2.5
  • G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 193
  • Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
  • Michael McCann, Artist Beware, Watson-Guptill Publications, New York City, 1979
  • R.D. Harley, Artists' Pigments c. 1600-1835, Butterworth Scientific, London, 1982
  • Matt Roberts, Don Etherington, Bookbinding and the Conservation of Books: a Dictionary of Descriptive Terminology, U.S. Government Printing Office, Washington DC, 1982
  • Henry Hodges, Artifacts: An Introduction to Early Materials and Technology, Ronald P. Frye, Kingston, Canada, 1988
  • The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 2283
  • The Dictionary of Art, Grove's Dictionaries Inc., New York, 1996 Comment: "Pigments"
  • CRC Handbook of Chemistry and Physics, Robert Weast (ed.), CRC Press, Boca Raton, Florida, v. 61, 1980 Comment: ref. index=2.5