Template:Infobox calcium

Calcium,  ₂₀Ca

Template:Infobox element/symbol-to-top-image-caption
General properties
Pronunciation	Template:Infobox element/pronunciation
Appearance	dull gray, silver; with a pale yellow tint
Standard atomic weight (Ar, standard)	Template:Infobox element/standard atomic weight
Mass number	Template:Infobox element/symbol-to-most-stable-isotope (most stable isotope)
Calcium in the periodic table
Template:Infobox element/periodic table
Atomic number (Z)	20
Group	Template:Infobox element/group
Period	period 4
Block	s-block
Element category	Template:Infobox element/category format
Electron configuration	[Ar] 4s2
Electrons per shell	2, 8, 8, 2
Physical properties
Phase at STP	solid
Melting point	1115 K ​(842 °C, ​1548 °F)
Boiling point	1757 K ​(1484 °C, ​2703 °F)
Density (near r.t.)	1.55 g/cm3
when liquid (at m.p.)	1.378 g/cm3
Heat of fusion	8.54 kJ/mol
[[Enthalpy of vaporization|Heat of Template:Engvar]]	154.7 kJ/mol
Molar heat capacity	25.929 J/(mol·K)
[[Vapor pressure|Template:Engvar pressure]] Template:Infobox element/vapor pressure table
Atomic properties
Oxidation states	Template:Infobox element/symbol-to-oxidation-state
Electronegativity	Pauling scale: 1.00
[[Ionization energy|Template:Engvar energies]]	1st: 589.8 kJ/mol 2nd: 1145.4 kJ/mol 3rd: 4912.4 kJ/mol (more)
Atomic radius	empirical: 197 pm
Covalent radius	176±10 pm
Van der Waals radius	231 pm
Template:Infobox element/spectral lines
Other properties
Crystal structure	​Template:Infobox element/crystal structure Template:Infobox element/crystal structure
Speed of sound thin rod	3810 m/s (at 20 °C)
Thermal expansion	22.3 µm/(m·K) (at 25 °C)
Thermal conductivity	201 W/(m·K)
Electrical resistivity	33.6 nΩ·m (at 20 °C)
Magnetic ordering	diamagnetic
Magnetic susceptibility	+40.0·10−6 cm3/mol
Young's modulus	20 GPa
Shear modulus	7.4 GPa
Bulk modulus	17 GPa
Poisson ratio	0.31
Mohs hardness	1.75
Brinell hardness	170–416 MPa
CAS Number	7440-70-2
History
Discovery and first isolation	Humphry Davy (1808)
Main isotopes of calcium
Template:Infobox element/isotopes table

Template:Infobox element/element navigation Template:Template reference list Two of these are named references. They may be cited in the containing article as

• <ref name="CIAAW2016" /> for the source Atomic weights of the elements 2013 (from subtemplates used by {{Infobox element}})
• <ref name="West" /> for the source edited by Kneck et al.