Calcium

Symbol CaAtomic 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

General descriptionNuclear data
Index

Periodic Table

Chemistry concepts
 
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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 . 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. 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. Magnesium with calcium forms the gem mineral diopside which has the composition CaMgSi2O6. Zoisite is another calcium silicate which is sometimes of gem quality.

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.

Titanium and calcium form the oxide perovskite, CaTiO3.

Atomic dataNuclear data
Index

Periodic Table

Chemistry concepts

Reference
Pauling
Ch. 26
 
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Calcium Nuclear Data

Z
A
Atomic
Mass (u)
Nuclear
Mass(GeV/c2
Binding
Energy(MeV)
Spin
Natural
Abund.
Half-life
Decay
Q
MeV
20
40
39.962591
37.2150
342.06
0
0.96941
stable
...
...
20
41
40.962278
38.1462
350.42
7/2
...
0.1My
EC
0.42
20
42
41.958618
39.0743
361.90
0
0.00647
stable
...
...
20
43
42.958766
40.0059
369.83
7/2
0.00135
stable
...
...
20
44
43.955481
40.9344
380.97
0
0.02086
stable
...
...
20
45
44.956185
41.8665
388.38
7/2
...
163.8d
b-
0.26
20
46
45.953690
42.7957
398.78
0
0.000040
stable
...
...
20
47
46.954543
43.7280
406.05
7/2
...
4.536d
b-
1.99
20
48
47.952533
44.6576
416.00
0
0.0019
stable
...
...
Atomic data
Index

Periodic Table

Chemistry concepts

Reference
Rohlf
 
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