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Atomic symbol: Ca |
Atomic number: 20 |
Atomic weight: 40.08 |
Atomic volume: 29.9 cm3/mol |
Density: 1.55 g/cm3 |
Period Number: 4 |
Group number: 2 |
Group name: Alkali Earth |
Element classification: Metal |
Phase at room temperature: Solid |
Melting Point: 1112.2 K |
Boiling point: 1767 K |
Heat of fusion: 8.540 kJ/mol |
Heat of vaporization: 153.60 kJ/mol |
Ionization Energy: 6.113 eV |
1st ionization energy: 589.8 kJ/mole |
2nd ionization energy: 1145.4 kJ/mole |
3rd ionization energy: 4911.8 kJ/mole |
Electronegativity: 1 |
Electron affinity: kJ/mole |
Specific heat: 0.63 J/gK |
Heat atomization: 178 kJ/mole atoms |
Shells: 2,8,8,2 |
Electron Shell Configuration: [Ar] 4s2 |
Minimum oxidation number: 0 |
Maximum oxidation number: 2 |
Minimum common oxidation number: 0 |
Maximum common oxidation no: 2 |
Appearance & Characteristics |
Structure:: hcp: hexagonal close pkd |
Color: silvery-white |
Hardness: 1.5 mohs |
Toxicity: ? |
Characteristics: burns brightly |
Uses: lime, cement |
Reaction with air: vigorous, =>CaO, Ca3N2 |
Reaction with 6M HCl: vigorous, =>H2, CaCl2 |
Reaction with 15M HNO3: vigorous, =>H2, Ca(NO3)2 |
Reaction with 6M NaOH: none |
Number of isotopes: 6 |
Oxide(s): CaO |
Hydride(s): CaH2 |
Chloride(s): CaCl2 |
Atomic Radius: 197 pm |
Ionic radius (1- ion): pm |
Ionic radius (1+ ion): pm |
Ionic radius (2- ion): pm |
Ionic radius (2+ ion): 114 pm |
Ionic radius (3+ ion): pm |
Thermal conductivity: 201 J/m-sec-deg |
Electrical conductivity: 255.754 1/mohm-cm |
Polarizability: 22.8 A^3 |
Source: Calcite (oxide) |
Relative abundance solar system: 4.786 log |
Abundance earth's crust: 4.65 log |
Estimated crustal abundance: 4.15×104 milligrams per kilogram |
Estimated oceanic abundance: 4.12×102 milligrams per liter |
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(L. 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. |
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. |
The metal has a silvery color, is rather hard, and is prepared by electrolysis of fused chloride and calcium fluoride ( to lower the melting point).
Chemically it is one of the alkaline earth elements; it readily forms a white coating of nitride in air, reacts with water, burns with a yellow-red flame.
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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.
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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. |
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SEKOM Handelsges.m.b.H.... |
Our company is a private firm founded in 1990 with aim to develop export and import with Russia. We do promote EU industrial and consumer goods in Russia and strongly support marketing of Russian and CIS industrial products and services.
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