| Description |
Silvery white, relatively soft metal obtained from fused calcium
chloride by electrolysis. Protected by oxide/nitride film and can be
worked as a metal. Used in alloys and in manufacture of Zr, Th, U, and
rare earth metals. Lime (CaO) used in metallurgy, water treatment,
chemicals, building, etc. Diagnostic tests:
Infusible calcium minerals glow with exaggerated incandescence in the
flame test (along with Sr, Mg, Zr, Zn, Ce - the "lime light
effect").
Sometimes, a orange red flame color may be observed if interfering Sr or
Na is not present (try calcite moistened with HCl).
In solution, (NH4)2CO3 will precipitate
calcium as an insoluble carbonate (along with Ba and Sr). Dissolve the
precipitate in HCl and try the flame test for Ca (orange red), Ba (green),
or Sr (purple red).
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