Copper carbonate , solubility

Cupric chloride or copper(II) chloride [7447-39 ], CUCI2, is usually prepared by dehydration of the dihydrate at 120°C. The anhydrous product is a dehquescent, monoclinic yellow crystal that forms the blue-green orthohombic, bipyramidal dihydrate in moist air. Both products are available commercially. The dihydrate can be prepared by reaction of copper carbonate, hydroxide, or oxide and hydrochloric acid followed by crystallization. The commercial preparation uses a tower packed with copper. An aqueous solution of copper(II) chloride is circulated through the tower and chlorine gas is sparged into the bottom of the tower to effect oxidation of the copper metal. Hydrochloric acid or hydrogen chloride is used to prevent hydrolysis of the copper(II) (11,12). Copper(II) chloride is very soluble in water and soluble in methanol, ethanol, and acetone. 

Calcium carbonate has normal pH and inverse temperature solubilities. Hence, such deposits readily form as pH and water temperature rise. Copper carbonate can form beneath deposit accumulations, producing a friable bluish-white corrosion product (Fig. 4.17). Beneath the carbonate, sparkling, ruby-red cuprous oxide crystals will often be found on copper alloys (Fig. 4.18). The cuprous oxide is friable, as these crystals are small and do not readily cling to one another or other surfaces (Fig. 4.19). If chloride concentrations are high, a white copper chloride corrosion product may be present beneath the cuprous oxide layer. However, experience shows that copper chloride accumulation is usually slight relative to other corrosion product masses in most natural waters. 

In seawater, the major chemical species of copper are Cu(OH)Cl and Cu(OH)2 and these account for about 65% of the total copper in seawater (Boyle 1979). The levels of copper hydroxide (Cu(OH)2) increase from about 18% of the total copper at pH 7.0 to 90% at pH 8.6 copper carbonate (CuC03) dropped from 30% at pH 7.0 to less than 0.1% at pH 8.6 (USEPA 1980). The dominant copper species in seawater over the entire ambient pH range are copper hydroxide, copper carbonate, and cupric ion (USEPA 1980). Bioavailability and toxicity of copper in marine ecosystems is promoted by oxine and other lipid soluble synthetic organic chelators (Bryan and Langston 1992). 

Copper Carbonate (Basic), CuCOi CutOH j. dark-green monoclinic crystals, insoluble in cold HiO decomposes in hot H 0, soluble in potassium cyanide. Malachite, a copper ore. is of this composition. Refined compound is used as a pigment. 

Symes J.L. and Kester D.R. (1984) Thermodynamic solubility studies of the basic copper carbonate mineral, malachite. Geochim. Cosmochim. Acta 48, 2219-2229. 

Andrew et o . ( 2) studied the effects of carbonate, orthophosphate, and pyrophosphate on the toxicity of copper(II) to Vapknia magna at constant pH and total hardness. They reported mortality rates and reciprocal survival times to be directly correlated with cupric and copper-hydroxo ion activities as de-tennined by equilibrium calculations. They also found toxicity to be negatively related to activities of soluble copper carbonate (CuC0°), and independent of total or dissolved copper concentration. Data for their set of experiments involving addition of orthophosphate are included in Table I but were not used in some... 

Properties Blue crystals. D 2.93 (25C). Slightly soluble in water soluble in acids and alcohol. Derivation (1) By decomposing copper carbonate with hydrofluoric acid and subsequent crystallization (2) fluorination of copper hydroxyfluoride at 525C. 

E27.2 Although copper is a relatively inert element, it does slowly oxidize on air, producing copper oxides (and upon longer exposure to the atmosphere, basic copper carbonates malachite and azurite). Both CU2O and CuO are basic oxides. Epidermis, the outermost layer of skin, is slightly acidic (pH about 5). When oxidized parts of the bracelet get in touch with acidic epidermis, a small amount of oxides dissolve and produce Cu, which is water soluble... 

The thermodynamic properties of C-Cu-Fe dilute liquid alloys of system at 1600°C were compiled and evaluated by [1974Sig]. The frrst-order free energy interaction coefficients for the C-Cu-Fe melts at 1600°C showing the effect of copper on solubility of carbon in the melt and vice versa are 0.066 and -0.06, respectively (die composition was expressed in mass%). 

Bel] Measurements of the activity of Cu in Fe rich C-Cu-Fe alloys using the Knudsen cell-mass spectrometer. Determination of copper and carbon solubility in liquid iron at 1600°C... 

Mor] Mori, T., Aketa, K., Ono, H., Sugita, H., Effects of Molybdenum, Wolfium and Copper on Solubility of Graphite in Liquid Iron and the Method of Calculation for the Activity of Carbon in a Multicomponent Solution (in Japanese), Tetsu-to-Hagane (J. Iron Steel Inst. Jpn), 46, 1429-1439 (1960) (Phase Relations, Thermodyn., 24) as quoted by [1979Cha]... 

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