Carbonate

Carbonate is an anion with a charge of -2 and an empirical formula of CO32-.

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For an aqueous solution, carbonate exists in three forms. In strongly basic conditions, the carbonate ion, CO32-, predominates. In weakly basic conditions, bicarbonate ion, HCO3- is prevalent. In acid conditions, aqueous carbon dioxide, CO2(aq), is the main form. This also contains a minute amount of carbonic acid, H2CO3. Thus sodium carbonate is basic, sodium bicarbonate is weakly basic, while carbon dioxide itself is a weak acid.

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In biological systems the enzyme, carbonic anhydrase, catalyzes this interconversion between carbon dioxide and carbonate ions. To test for the presence of the carbonate anion in a salt, the addition of dilute hydrochloric acid will yield carbon dioxide gas.

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Carbonate-containing salts are industrially and mineralogically

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ubiquitous. The term "carbonate" is also commonly used to refer to one of these salts or carbonate minerals. Most common is calcite, or calcium carbonate, the chief constituent of limestone. The process of removing these salts is called calcination.

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The term is also used as a verb, to describe the process of

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raising carbonate and bicarbonate concentrations in water, see also carbonated water, either by the introduction under pressure of carbon dioxide gas into the water, or by dissoving carbonate or bicarbonate salts into the water.

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At one time, it was thought that the presence of carbonates in rock was unequivocal evidence for the presence of liquid water. Recent observations of two planetary nebulae reported in the January 17, 2002 issue of the scientific journal Nature indicate that carbonates can form in interplanetary space.

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Carbonates were detected in the Gusev Crater on Mars by the Mars Exploration Rover Spirit on January 9, 2004. http://www.jpl.nasa.gov/mer2004/rover-images/jan-09-2004/captions/image-10.html

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Anion: REDIRECT Ion...

Empirical formula: In chemistry, the empirical formula of a chemical is a simple expression of the relative number of each type of atom (called a chemical element) in it. An empirical formula makes no reference to isomerism, structure, or absolute number of atoms. Empirical formulas are the standard for ionic compound...

Aqueous solution: An aqueous solution is a solution in which the solvent is water. It is usually shown in chemical equations by appending (aq) to the relevant formula. The word aqueous means pertaining to, related to, similar to, or dissolved in water. As water is an excellent solvent as well as naturally abundant, i...