Calcium

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Animated Calcium

History

From the Latin word calx, lime. Though lime was prepared by the Romans in the first century under the name calx, the metal was not discovered until 1808. After learning that Berzelius and Pontin prepared calcium amalgam by electrolyzing lime in mercury, Davy was able to isolate the impure metal.

Sources

Calcium, a metallic element, is fifth in abundance in the earth's crust, of which it forms more than 3%. It is an essential constituent of leaves, bones, teeth, and shells. Never found in nature uncombined, it occurs abundantly as limestone, gypsum, and fluorite. Apatite is the fluorophosphate or chlorophosphate of calcium.

Compounds

Its natural and prepared compounds are widely used. Quicklime (CaO), which is made by heating limestone that is changed into slaked lime by carefully adding water, is the great base of chemical refinery with countless uses.

When mixed with sand, it hardens mortar and plaster by taking up carbon dioxide from the air. Calcium from limestone is an important element in Portland cement.

Solubility of the carbonate in water containing carbon dioxide is high, which causes the formation of caves with stalactites and stalagmites and is responsible for hardness in water. Other important compounds are the carbide, chloride, cyanamide, hypochlorite, nitrate, and sulfide.

Uses

The metal is used as a reducing agent in preparing other metals such as thorium, uranium, zirconium, etc., and is used as a deoxidizer, desulfurizer, or decarburizer for various ferrous and nonferrous alloys. It is also used as an alloying agent for aluminum, beryllium, copper, lead, and magnesium alloys, and serves as a "getter" for residual gases in vacuum tubes, etc.

General Info

AtomicNumber
20
Symbol
Ca
Name
Calcium

Atomic Info

Appearance
AtomicWeight
40.078(4)
Color
3DFF00
ElectronicConfiguration
[Ar] 4s2
ElectronegativityInPauling
1
AtomicRadiusInPM
174
IonRadiusInPM
100 (+2)
VanDerWaalsRadiusInPM
IEinKJmol
590
EAinKJmol
-2
OxidationStates
2
StandardState
solid
BondingType
metallic
MeltingPoint
1115
BoilingPoint
1757
Density
1.55
State
Alkaline earth metal
DiscoveredYear
Ancient