Calcium carbonate ( CaCO < sub > 3 </ sub >) is one of the common compounds of calcium.

* Calcium carbonate ( CaCO < sub > 3 </ sub >) is used in manufacturing cement and mortar, lime, limestone ( usually used in the steel industry ) and aids in production in the glass industry.

The Calcium carbonate, from which coral skeletons are made is just over 60 % Carbon dioxide.

Calcium carbonate dissolved into water may precipitate out where the water discharges some of its dissolved carbon dioxide.

Calcium carbonate is deposited where evaporation of the water leaves a solution supersaturated with the chemical constituents of calcite.

* Calcium carbonate

Calcium carbonate is susceptible to even a weak acid solution because the crystals of calcium carbonate react with the acetic acid in the vinegar to form calcium acetate and carbon dioxide.

When the cement paste exposed to the air and meteoric water reacts with the atmospheric CO < sub > 2 </ sub >, portlandite and the Calcium Silicate Hydrate ( CSH ) of the hardened cement paste become progressively carbonated and the high pH gradually decreases from 13. 5 – 12. 5 to 8. 5, the pH of water in equilibrium with calcite ( calcium carbonate ) and the steel is no longer passivated.

The coarse character of the hairs is due to Silicon dioxide and Calcium carbonate.

Calcium carbonate, long used as the coating of paper, was now being used as an important filler as the paper industry converted from acid-based paper making systems to alkaline systems.

Calcium carbonate has two forms, the stable calcite, and the metastable aragonite, which is stable within a reasonable range of chemical environments but rapidly becomes unstable outside this range.

Calcium carbonate dissolves at a rate dependent upon local carbonate chemistry.

Calcium carbonate is used by living organisms to manufacture carbonaceous tests and shells.

Calcium and bicarbonate ions within the water are then able to combine, to form calcium carbonate ( CaCO < sub > 3 </ sub >) as a precipitate.

Calcium carbonate is the principle constituent of most limestones.

# REDIRECT Calcium carbonate

Calcium carbonate scales formed in water-heating systems are called limescale.

Calcium carbonate formations are associated with regions where meteoric waters become enriched with calcium carbonate by direct dissolution of CaCO3-rich rocks underground only to resurface and re-precipitate calcite.

: A02AC01 Calcium carbonate

: A12AA04 Calcium carbonate

** Calcium carbonate

Calcium ( ) is the chemical element with symbol Ca and atomic number 20.

Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust.

Calcium is also the fifth-most-abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, magnesium, and sulfate.

Calcium is essential for living organisms, in particular in cell physiology, where movement of the calcium ion Ca < sup > 2 +</ sup > into and out of the cytoplasm functions as a signal for many cellular processes.

Calcium, with a density of 1. 55 g / cm < sup > 3 </ sup >, is the lightest of the alkaline earth metals ; magnesium ( specific gravity 1. 74 ) and beryllium ( 1. 84 ) are more dense, although lighter in atomic mass.

Calcium has a higher electrical resistivity than copper or aluminium, yet weight-for-weight, due to its much lower density, it is a rather better conductor than either.

Calcium is the fifth-most-abundant element by mass in the human body, where it is a common cellular ionic messenger with many functions, and serves also as a structural element in bone.

Calcium, combined with phosphate to form hydroxylapatite, is the mineral portion of human and animal bones and teeth.

Calcium hydroxide ( slaked lime ) is used in many chemical refinery processes and is made by heating limestone at high temperature ( above 825 ° C ) and then carefully adding water to it.

Calcium is not naturally found in its elemental state.

Calcium is used

* Calcium hydroxide solution ( Ca ( OH )< sub > 2 </ sub >) ( also known as limewater ) is used to detect the presence of carbon dioxide by being bubbled through a solution.

* Calcium arsenate ( Ca < sub > 3 </ sub >( AsO < sub > 4 </ sub >)< sub > 2 </ sub >) is used in insecticides.

* Calcium carbide ( CaC < sub > 2 </ sub >) is used to make acetylene gas ( for use in acetylene torches for welding ) and in the manufacturing of plastics.

* Calcium chloride ( CaCl < sub > 2 </ sub >) is used in ice removal and dust control on dirt roads, in conditioner for concrete, as an additive in canned tomatoes, and to provide body for automobile tires.

* Calcium cyclamate ( Ca ( C < sub > 6 </ sub > H < sub > 11 </ sub > NHSO < sub > 3 </ sub >)< sub > 2 </ sub >) was used as a sweetening agent but is no longer permitted for use because of suspected cancer-causing properties.

* Calcium gluconate ( Ca ( C < sub > 6 </ sub > H < sub > 11 </ sub > O < sub > 7 </ sub >)< sub > 2 </ sub >) is used as a food additive and in vitamin pills.

* Calcium hypochlorite ( Ca ( OCl )< sub > 2 </ sub >) is used as a swimming pool disinfectant, as a bleaching agent, as an ingredient in deodorant, and in algaecide and fungicide.

* Calcium permanganate ( Ca ( MnO < sub > 4 </ sub >)< sub > 2 </ sub >) is used in liquid rocket propellant, textile production, as a water sterilizing agent and in dental procedures.

* Calcium phosphate ( Ca < sub > 3 </ sub >( PO < sub > 4 </ sub >)< sub > 2 </ sub >) is used as a supplement for animal feed, fertilizer, in commercial production for dough and yeast products, in the manufacture of glass, and in dental products.