Calcium acetate is a

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

which is a

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quant ...

of acetic acid. It has the formula Ca(C₂H₃O₂)₂. Its standard name is calcium acetate, while calcium ethanoate is the systematic name. An older name is acetate of lime. The anhydrous form is very

hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substan ...

; therefore the mono hydrate (Ca(CH₃COO)₂•H₂O) is the common form.

Production

Calcium acetate can be prepared by soaking calcium carbonate (found in eggshells, or in common carbonate rocks such as

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

marble Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite. Marble is typically not foliated (layered), although there are exceptions. In geology, the term ''marble'' refers to metamorphose ...

) or

hydrated lime Calcium hydroxide (traditionally called slaked lime) is an inorganic compound with the chemical formula Ca( OH)2. It is a colorless crystal or white powder and is produced when quicklime (calcium oxide) is mixed or slaked with water. It has ma ...

vinegar Vinegar is an aqueous solution of acetic acid and trace compounds that may include flavorings. Vinegar typically contains 5–8% acetic acid by volume. Usually, the acetic acid is produced by a double fermentation, converting simple sugars to eth ...

: :CaCO₃(s) + 2CH₃COOH(aq) → Ca(CH₃COO)₂(aq) + H₂O(l) + CO₂(g) :Ca(OH)₂(s) + 2CH₃COOH(aq) → Ca(CH₃COO)₂(aq) + 2H₂O(l) Since both reagents would have been available pre-historically, the chemical would have been observable as crystals then.

Uses

* In kidney disease, blood levels of

phosphate In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid . The phosphate or orthophosphate ion is derived from phosph ...

may rise (called

hyperphosphatemia Hyperphosphatemia is an electrolyte disorder in which there is an elevated level of phosphate in the blood. Most people have no symptoms while others develop calcium deposits in the soft tissue. Often there is also low calcium levels which can ...

) leading to bone problems. Calcium acetate binds phosphate in the diet to lower blood phosphate levels. * Calcium acetate is used as a food additive, as a stabilizer, buffer and

sequestrant A sequestrant is a food additive which improves the quality and stability of foods. A sequestrant forms chelate complexes with polyvalent metal ions, especially copper, iron and nickel, which can prevent the oxidation of the fats in the food. Se ...

, mainly in candy products under the number E263. *

Tofu Tofu (), also known as bean curd in English, is a food prepared by coagulating soy milk and then pressing the resulting curds into solid white blocks of varying softness; it can be ''silken'', ''soft'', ''firm'', ''extra firm'' or ''super f ...

is traditionally obtained by coagulating

soy milk Soy milk (simplified Chinese: 豆浆; traditional Chinese: 豆漿) also known as soya milk or soymilk, is a plant-based drink produced by soaking and grinding soybeans, boiling the mixture, and filtering out remaining particulates. It is a sta ...

with

calcium sulfate Calcium sulfate (or calcium sulphate) is the inorganic compound with the formula CaSO4 and related hydrates. In the form of γ-anhydrite (the anhydrous form), it is used as a desiccant. One particular hydrate is better known as plaster of Paris ...

. Calcium acetate has been found to be a better alternative; being soluble, it requires less skill and a smaller amount.J. Y. Lu, Eloise Carter and R. A. Chung (1980): "Use of Calcium Salts for Soybean Curd Preparation" ''Journal of Food Science'', volume 45, issue 1, pages 32–34 * Because it is inexpensive, calcium acetate was once a common starting material for the synthesis of

acetone Acetone (2-propanone or dimethyl ketone), is an organic compound with the formula . It is the simplest and smallest ketone (). It is a colorless, highly volatile and flammable liquid with a characteristic pungent odour. Acetone is miscib ...

before the development of the cumene process: : Ca(CH₃COO)₂ → CaCO₃(s) + (CH₃)₂CO * A saturated solution of calcium acetate in alcohol forms a semisolid, flammable gel that is much like "canned heat" products such as

Sterno Sterno is a brand of jellied, denatured alcohol sold in a can and meant to be burned directly in its can. Its primary uses are in food service for buffet heating, in the home for fondue, and as a chafing fuel for heating chafing dishes. Other ...

. Chemistry teachers often prepare "California Snowballs", a mixture of calcium acetate solution and

ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a ...

. The resulting gel is whitish in color, and can be formed to resemble a snowball.

Natural occurrence

Pure calcium acetate is yet unknown among minerals. calcium acetate chloride is listed as a known mineral, but its genesis is likely anthropogenic (human-generated, as opposed to naturally occurring) and it may soon be discredited.

References

{{Acetates Acetates Calcium compounds Phosphate binders E-number additives