Malachite CuCO

FIGURE 16.13 Three important copper ores (from left to right) chalcopyrite, CuFeS2 malachite, CuCO,-Cu(OH)2 and chalcocite, Cu2S. 

Global copper production during the past 60 centuries is estimated at 307 million metric tons, most of which (79%) occurred since 1900 aimual global production of copper is now estimated at 13.6 million tons. Copper occurs naturally in many minerals and as uncombined metal. The three most important sources of copper are chalcocite (Cu2S), chal-copyrite (CuFeS2), and malachite (CuCOs Cu(OH)2). 

In drinking water with dissolved carbonic acid, the formation of malachite CuCOs Cu(OH)2 with a blue to green color is often observed [41]. 

Malachite CuCO iCuCOH), Brochanite CuS04 3Cu(0H)2 Atacamite CuCl2 3Cu(OH>>... 

Copper(I) carbonate (Cu + CO Cu Oj) is known as cuprous carbonate since coppers ion is +1 copper(II) carbonate (Cu + CO — CuCO ) is known as cupric carbonate, which is also known as the green copper mineral malachite, used in pigments, as an insecticide, as a cosmetic astringent, and as a plant fungicide to prevent smut. 

Many of the minerals in the Earth s crust are not simple ionic compounds consisting of one type of cation such as Cu and one type of anion such as carbonate, COs ". These more complex compounds can be classified as double (or triple or quadruple) salts. (These salts are also referred to as ternary or quaternary.) That is, they contain more than one type of cation and/or more than one type of anion. For example, one of the conunon ores of copper is malachite, which has the formula Cu2C03(0H)2. This is an ionic compound that contains the Cu " ion and both the carbonate and hydroxide anions. Double salts can be thought of as combinations (but not mixtmes) of two or more simple salts. Malachite can be visualized as CuCOs -1- Cu(OH)2. Malachite is frequently found with azurite, which has the formula Cu3(C03)2(0H)2. Azurite simply has a different ratio of the two simple salts 2 CuCOs + Cu(OH)2. 

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