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Calcium (Ca)

Ordnungszahl: 20
Name: Calcium
Namensursprung: Latin: calx, calcis (lime).
Entdeckung: 1808 by Sir Humphrey Davy in England
Beschreibung: Fairly hard, silvery-white metal. Fifth most abundant element in the earth's crust (41,500 ppm). Occurs only in compounds.
Vorkommen: Obtained from minerals like chalk, limestone and marble. Pure metal is produced by replacing the calcium in lime (calcium carbonate, CaCO3) with aluminium in hot, low pressure retorts.
Verwendung: Used by many forms of life to make shells and bones. Virtually no use for the pure metal, however two of its compounds are, lime (CaO) and gypsum (CaSO4), are in great demand by a number of industries.
Gruppe: Alkali Earth Metal
Atomgewicht: 40.078
Schmelzpunkt: 839°C
Siedepunkt: 1484°C
Dichte bei 293 K: 1.55 g/cm³
Aggregatszustand bei Raumtemperatur: Solid
Schalen: 2,8,8,2
Orbitale: [Ar] 4s2
Valenzen: 2
1. Ionisierungs- potential: 6.1132 V
2. Ionisierungs- potential: 11.871 V
3. Ionisierungs- potential: 50.908 V
Atomradius: 2.23 Å
Spezifische Wärme: 0.63 J/gK
Verdampfungswärme: 153.60 kJ/mol
Schmelzwärme: 8.540 kJ/mol
Thermischer Ausdehnungskoeffizient: 22.3 10-6 K-1
Röntgenemission Energie / Wellenlänge:
  KA KB LA LB MA MB      
eV 3690.61 4012.86 341.276 344.979 0 0      
Å 3.35948 3.0897 36.3299 35.94 0 0      
Röntgenabsorption Energie / Wellenlänge:
  K L-I L-II L-III M-I M-II M-III M-IV M-V
eV 4039 0 352.9 349.31 0 0 0 0 0
Å 3.06971 0 35.1333 35.4944 0 0 0 0 0
Röntgen Fluoreszenz Ausbeute:
  KA KB LA LB MA MB      
  16.3% 0% 0.1% 0% 0% 0%      
Nuklide:
  Anteil Gewicht Spin Halbwertszeit Zerfallsmodus
Ca40 96.97% 39.9626 0   Stable
Ca41 0% 41 7/2 1.03E05y EC
Ca42 0.64% 41.9586 0   Stable
Ca43 0.145% 42.9588 7/2   Stable
Ca44 2.06% 43.9555 0   Stable
Ca45 0% 44.956 7/2 162.7d β-
Ca46 0.0033% 45.9537 0   Stable
Ca47 0% 46.954 7/2 4.536d β-
Ca48 0.18% 47.9525 0   Stable
Ca49 0% 49 3/2 8.72m β-


book | by Dr. Radut