Calcium
Soft grey metallic element belonging to group 2 of the periodic table. Used a reducing agent in the extraction of thorium, zirconium and uranium. Essential element for living organisms.
Gallery
Jurii, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons, source: https://images-of-elements.com/calcium.php
Emission spectrum
Physical Propertiesmass · density · phase · crystal
Atomic Mass
40.0780Da
Density
1.5400g/cm³
Phase (STP)
Solid
Melting Point
1115.2K
Boiling Point
1757.2K
Molar Heat
0.6470J/(mol·K)
Crystal Structure
FCC
Lattice Constant
5.580Å
Atomic Radiiatomic · covalent · van der Waals
Atomic (Empirical)
180.00pm
Covalent
171.00pm
Van der Waals
231.00pm
Electronic Propertieselectronegativity · ionization · affinity
Electron Configuration
[Ar] 4s2
Electron Shells
2, 8, 8, 2
Electronegativity
1Pauling
Electron Affinity
0.0kJ/mol
1st Ionization Energy
6.1kJ/mol
Oxidation States
+2
Orbital DiagramAufbau · Hund's rule · Pauli exclusion
Full: 1s2 2s2 2p6 3s2 3p6 4s2Short: [Ar] 4s2
Ionization Energies (20 known)
Emission Spectrumvisible range · characteristic spectral lines
Abundanceby mass
Log scale · ppm = parts per million by mass
Biological Role
Main mineral in bones and teeth. Essential for muscle contraction, blood clotting, and signaling.
Discovery
Discovered By
Sir Humphrey Davy
Named By
—
Year
1808
Nuclear Data
Known Isotopes
29
Stable Isotopes
7
Stable Mass Numbers
33, 34, 40, 42, 43, 44, 46
Natural isotopic abundance (IUPAC recommended values)
Isotopes of Ca29 known
| Nuclide | Z | N | Mass (AMU) | Half-life | Decay | Jπ | Abundance |
|---|---|---|---|---|---|---|---|
| 33Castable | 20 | 13 | 33.033312 | Stable | p | 5/2+ | — |
| 34Castable | 20 | 14 | 34.015985 | Stable | 2p | 0+ | — |
| 35Ca | 20 | 15 | 35.005572 | 25.7 ms | β⁺ (1%), β⁺p (0.958%), 2p (0.042%) | 1/2+ | — |
| 40Castable | 20 | 20 | 39.962591 | Stable | 2β⁺ | 0+ | 9694.1000% |
| 42Castable | 20 | 22 | 41.958618 | Stable | stable (1%) | 0+ | 64.7000% |
| 43Castable | 20 | 23 | 42.958766 | Stable | stable (1%) | 7/2- | 13.5000% |
| 44Castable | 20 | 24 | 43.955481 | Stable | stable (1%) | 0+ | 208.6000% |
| 46Castable | 20 | 26 | 45.953688 | Stable | 2β⁻ | 0+ | 0.4000% |
| 48Ca | 20 | 28 | 47.952523 | 56000000000 Gy | 2β⁻, β⁻ | 0+ | 18.7000% |
| 59Ca | 20 | 39 | 59.006237 | Unknown | β⁻, β⁻n, 2n | 5/2- | — |
| 60Ca | 20 | 40 | 60.011809 | Unknown | β⁻, β⁻n, 2n | 0+ | — |
| 61Ca | 20 | 41 | 61.020408 | Unknown | β⁻, β⁻n, 2n | 1/2- | — |