Calcium
Calcium General
| Name:Calcium | Symbol:Ca |
| Type:Alkali Earth metal | Atomic weight:40.078 |
| Density @ 293 K:1.55 g/cm3 | Atomic volume:29.9 cm3/mol |
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Discovered:
Compounds such as lime (CaO, calcium oxide) were prepared by the Romans in the first century under the name calx. The element calcium was first isolated by Sir Humphry Davy in 1808 in London. |
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Calcium States
| State (s, l, g):solid | |
| Melting point:1115 K (842 °C) | Boiling point:1771 K (1484 °C) |
Calcium Energies
| Specific heat capacity:0.63 J g-1 K-1 | Heat of atomization:178 kJ mol-1 |
| Heat of fusion: 8.54 kJ mol-1 | Heat of vaporization :153.6 kJ mol-1 |
| 1st ionization energy:589.8 kJ mol-1 | 2nd ionization energy: 1145.4 kJ mol-1 |
| 3rd ionization energy:4911.8 kJ mol-1 | Electron affinity:2 kJ mol-1 |
Calcium Oxidation & Electrons
| Shells:2,8,8,2 | Electron configuration:[Ar] 4s2 |
| Minimum oxidation number:0 | Maximum oxidation number:2 |
| Min. common oxidation no.:0 | Max. common oxidation no.:2 |
| Electronegativity (Pauling Scale): 1 | Polarizability volume:22.8 Å3 |
Calcium Appearance & Characteristics
| Structure:ccp: cubic close packed | Color:silvery-white |
| Hardness:1.75 mohs | |
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Harmful effects:
Non toxic and an essential metal for living organisms. |
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Characteristics:
Calcium is reactive and, for a metal, soft (with difficulty, it can be cut with a knife). Uses: Calcium forms alloys with aluminum, beryllium, copper, lead, and magnesium. |
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Calcium Reactions
| Reaction with air:vigorous, ⇒ CaO, Ca3N2 | Reaction with 6 M HCl:vigorous, ⇒ H2, CaCl2 |
| Reaction with 15 M HNO3:vigorous, ⇒ H2, Ca(NO3)2 | Reaction with 6 M NaOH:none |
Calcium Compounds
| Oxide(s): CaO | Chloride(s):CaCl2 |
| Hydride(s):CaH2 |
Calcium Radius
| Atomic radius:180 pm | Ionic radius (1+ ion):pm |
| Ionic radius (2+ ion):114 pm | Ionic radius (3+ ion):pm |
| Ionic radius (2- ion):pm | Ionic radius (1- ion):pm |
Calcium Conductivity
| Thermal conductivity:201 W m-1 K-1 | Electrical conductivity:0.313 x 106 S cm-1 |
Calcium Abundance & Isotopes
| Abundance earth's crust: 4.2 % by weight , 2.2 % by moles | |
| Abundance solar system:70 parts per million by weight, 2 parts per million by moles | |
| Cost, pure:$20 per 100g | |
| Cost, bulk: $ per 100g | |
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Source:
Calcium occurs in nature in various minerals including limestone (calcium carbonate), gypsum (calcium sulfate) and fluorite (calcium fluoride). Commercially it can be made by the electrolysis of molten calcium chloride, CaCl2. The pure metal can also be produced by replacing the calcium in lime (CaCO3) with aluminum in hot, low pressure retorts. |
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Isotopes:
19 whose half-lives are known, with mass numbers 35 to 53. Of these, five are stable: 40Ca, 42Ca, 43Ca, 44Ca and 46Ca. 97% of naturally occurring calcium is in the form of 40Ca. |
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Calcium Other
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Other:
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