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Home >> Chemistry Dictionary >> Calcium Chloride Calcium Phosphates
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Calcium carbonate.
CaCO3. Occurs naturally (See calcium). Precipitated from Ca(OH)2 Solution by CO2 but dissolves in excess CO2 to form the hydrogen carbonate (ca(HCO3)2.
Calcination.
The formation of a calcium carbonate deposit from hard water. See hardness of water.
Calcinite.
A mineral form of potassium hydrogencarbonate, KHCO3.
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Calcite
One of the most common and widespread minerals, consisting of crystalline calcium carbonate. CaCO3 Calcite crystallizes in the rhombohedral system ; it is usually colourless or white and has a hardness of 3 on the Moh’s scale. It has the property of double refraction, which is apparent in Iceland Spar —the transparent variety of calcite. It is an important rock-forming mineral and is major constituent in limestones, marbles, and carbonates.
Calcium chloride
CaCl2 Occurs naturally as tachydrite, CaCl2. 2MgCl2, 12H2O and in sea and mineral waters. Prepared pure from CaCO3 and HCl and gives CaCl2, 6H2O, m.p. 30°C, CaCl2, 4H2O, CaCl2, 2H2O and the anhydrous salt.
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Gives adducts with alcohols and ammonia. Obtained commercially from natural brines and from the ammonia soda process for NaCO3 Used for de-icing roads, dust control, as an antifreeze in concrete mixes and in solution in refrigeration plants.
Calcium Cyanamide
CaNCN. Prepared from N2 and CaC2 at 1100°C. Used a fertilizer; on hydrolysis gives NH3 and urea in the soil. Gives cyanides on fusion with C and Na2CO3 at 1200°C.
Calcium ethanoate.
[Ca(O2CCH3)2 or 1.H2O]. It is obtained by the reaction between CaCO3 and ethanoic acid. It is used in calico printing and to prepare other ethanoates.
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Calcium fluoride
Refers to a white crystalline solid. It occurs in nature as the mineral fluoride.
Calcium hydride,
CaH2, White solid (Ca(solid in NH3) and hydrogen). Releases hydrogen with water (hydrolith), used as a drying agent and a reducing agent in metallurgy.
Calcium hydroxide, slaked lime.
Ca(OH)3. The powder from the action of an equivalent quantity of water on CaO is slaked lime; a suspension with excess water is milk of lime, a clear solution of Ca(OH)2 in water is limewater. Used as an industrial alkali and in the preparation of mortar which is used as a building material.
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Calcium oxide,
Lime, quicklime, CaO. A white solid with the NaCl structure produced by heating CaCO3 to high temperatures Commercially lime is produced by heating CaCO3 to a temperature between 900°C and 1200°C.
Calcium Phosphates
The orthophosphates, (Ca3(PO4)2 occurs naturally and is precipitated from Ca2+ solution by phosphate (used as a polymerization aid for styrene and nutritional supplement). CaHPO4, 2H2O (CaCl2) solution plus Na2 HPO4) and Ca(H2PO4)2, H2O (other phosphates plus H3PO4) are also known. The latter compound is the principal active ingredient of Superphosphates. Calcium phosphates are used in foodstuffs.
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Calcium silicates.
Important minerals also present in slag and cements.
Calcium sulphate
CaSO4 Occurs naturally as anhydride, and as CaSO4, 2H2O as gypsum, selenite, satin-spar, alabaster, Natural anhydride and CaSO4 prepared by dehydrating the dihydrate above 650°C is only slowly soluble in water and is used aa a filler for paper and other materials (see also stain white). CaSO4 prepared by dehydration of the dehydrate at 60—90°C is used as a drying agent. CaSO4.0.5H2O, prepared by heating gypsum at 130°C, is used as plaster of Paris. Gypsum and anhydride are used for H2SO4 production and gypsum is used as a soil additive and as a soil additive and as an inert additive to pharmaceuticals and insecticides.
Calcium sulphide,
CaS. Formed form H2S and limewater or CaSO4 charcoal at 1000°C. The impure material is luminescent Used as a depilatory.
Calcium sulphite,
CaSO3 Formed form SO2 and limewater or CaCl2 plus a sulphite as a precipitate, dissolves in excess SO2. Used for sterilization and for dissolving the lignin in wood pulp in paper manufacture.
Calgon.
A trade name for water softening agent sodium metaphosphate used as a washing powder and cleansing agent.
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