Mineral Species containing Chromium (Cr)

Element Properties, Isotopic Compositions for Chromium

**Chromium (Cr) Element Properties**
Atomic Mass	51.9961
Atomic Number	24
Name Origins	Greek, chroma = "color"
Year Discovered	1780
Discovery Credits	N. L. Vanquelin at Paris, France
Remarks	Hard, blue-white metal. Soluble in HCl and H₂SO₄ but not HNO₃, H₃PO₄ or HClO₄ due to formation of protective layer. Resists oxidation in air. Main use in alloys, chrome plating, and metal ceramics. Diagnostic tests: Chromium gives a borax bead test in the reducing flame a color which is yellow to red (hot) and yellowish green (cold). Under the reducing flame the bead color is a fine emerald green, hot and cold. Chromium gives a Na₂(NH₄)(PO₄) bead a dirty green color (hot) and a fine green color (cold). In solution, the addition of NH₄OH produces a green precipitate of Cr(OH)₃. Note: chromium's name is in reference to the various colors a solution will have depending on the oxidation state Cr²⁺ (yellow), Cr³⁺ (green), or Cr⁶⁺ (orange).
References	Emsley, J., 1991; THE ELEMENTS : Sec. Ed., Clarendon Press, Oxford, 251 p.
See Also	WebElements, ChemiCool

**Naturally Occurring Isotopes**
Symbol	Isotope Mass	Isotope Nuclide Number	Isotope Number	Natural Abundance	Half-life Units
Cr	49.946046	50	24	4.3500%	Stable
Cr	51.940509	52	24	83.7900%	Stable
Cr	52.940651	53	24	9.5000%	Stable
Cr	53.938882	54	24	2.3600%	Stable

Chromium (Cr) Minerals sorted by Mineral Name

Click here for List sorted by Weight Percent

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**103 Minerals containing Chromium (Cr) sorted by Mineral Name**
% Cr	Mineral Name	Chemical Formula	MW
44.56 % Cr	Zincochromite	ZnCr2O4	233.38
1.32 % Cr	Zoltaiite !	BaV++++2V+++12Si2O27	1,340.36

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