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Fine Art -chromium: Approximately 0.037% of the ign< ous rock in the efine art -chromiumh's crust is chromium. Becaus chromium is such an active element, it is IK found in the free state in nature. The most in portant commercial source of chromium is th mineral chromite, or ferrous chromite, which cor tains iron in the divalent state and chromium i the trivalent state. The chemical formula c the ore can be represented either as FeO'Cr20 FeCr2O4, or Fe(CrO2)2, but in each case there i about 68% Cr2O3 and 32% FeO. Virtually all high grade chromite ore is from the Transvaal, in Soutl Africa; low-grade ores are mined in Montana California, and Oregon.CHROMIUM, kro'me-am, symbol Cr, is a metal element. The French chemist Louis Nico Vauquelin isolated it from lead chromate in 17! The name of the element is derived from t Greek word chroma, meaning "color," becat many of the compounds of chromium, are ve highly colored. Properties. Chromium is a hard, blue-wh metal with a brilliant luster. Its melting point 1550°C (2822°F), and its boiling point is 2482' (4500°F). Chromium is a transitional eleme located in column VIB of the periodic table. '. atomic number is 24, and its atomic weight 51.996. There are four naturally occurring is topes of the element-s°Cr, 52Cr, 53Cr, and 54( The most abundant isotope is G2Cr.
The production of chromium chemicals—principally sodium bichromate—is still another important use of chromite, although the quantity of ore consumed for this purpose is relatively small. The major industrial applications of chromium chemicals are in the manufacture of pigments, leather tanning, textiles, and electroplating. |
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