Calcium

Symbol

Ca

Atomic number

20

Atomic mass	40.08		Thermal conductivity	2.00
Atomic radius	2.23		Covalent radius	1.74
Density	1.55		Atomic volume	29.9
Melting point	1112		Oxidation states	2
Boiling point	1757		Stable isotopes	6
Heat of vapor.	153.6		Electronegativity	1.00
Heat of fusion	8.54		First ionization	6.113
Specific heat	0.63		Electrical conduct.	...

Electron configuration

Calcium

Calcium is a silvery white metal which is chemically active, reacting with cold water to produce calcium hydroxide, Ca(OH)2. It burns readily in air, producing calcium oxide, CaO, and calcium nitride, Ca3N2. Calcium is used as a deoxidizer to remove oxygen from iron and steel in their production and in the production of copper and copper alloys. Calcium is used as a constituent in lead alloys used for bearings and the sheaths for electric cables. Calcium is also used in aluminum alloys.

Calcium is one of the big 8 elements in the Earth's crust, being the fifth most abundant element at about 3.6% by weight. In nature, calcium occurs in the form of gypsum, which is calcium sulfate CaSO₄.2H₂O . Calcium sulfate, CaSO₄, without the attached water molecules also occurs in the form of the mineral anhydrite. Gypsum is used widely for wallboard and for conversion into plaster of Paris. Plaster of Paris is created by heating gypsum to a little above 100°C where it loses three-quarters of its water of hydration and becomes the powdered substance CaSO₄. 1/2 H₂O.

It also occurs in the abundant mineral calcite, CaCO₃ and in Aragonite, also with composition CaCO₃. Another carbonate of calcium is Whewellite. Along with barium it forms the carbonate mineral alstonite. It is a constituent of the plagioclase form of feldspar and contained in hornblende. Calcium is found with boron in the silicate minerals danburite, datolite and Howlite and in the oxide inyoite. It is contained in the minerals dolomite and Powellite.

Calcium appears in the carbonate mineral Bensonite. Calcium is a constituent of many silicate minerals. The simple calcium silicate, CaSiO₃, occurs in the mineral wollastonite. A hydrated form of calcium silicate is okenite, Ca₁₀Si₁₈O₄₆.18H₂O. Manganese with calcium forms the mineral bustamite. Manganese with calcium and lead forms the mineral roeblingite. Magnesium with calcium forms the gem mineral diopside which has the composition CaMgSi₂O₆. Zoisite is another calcium silicate which is sometimes of gem quality. Titanium and calcium form the silicate titanite, CaTiSiO₅, which can form gem-quality crystals.

Calcium combines with fluorine nature to form minerals such as fluorite, CaF₂, which can produce gem quality crystals. Also occurring as a mineral is fluorapatite, Ca₅(PO₄)₃F, which is a constituent of bones and teeth. A small percentage of fluorapatite along with the more abundant calcium phosphates in teeth can make them more resistant to decay.

Graftonite is a phosphate mineral of iron, manganese and calcium. Chalcosiderite is a phosphate mineral of iron and calcium. Roselite is an arsenate that contains cobalt, magnesium and calcium and forms red crystals.

Titanium and calcium form the oxide perovskite, CaTiO₃.

Calcium Nuclear Data