Calcium (Ca)

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.

Atomic Number	20
Atomic Weight	40.078
Mass Number	40

Group	2
Period	4
Block	s

Protons	20 p⁺
Neutrons	20 n⁰
Electrons	20 e^-

Properties

Energy
Atomic Radius	180 pm 270 pm
Molar Volume	29.9 cm³/mol
Covalent Radius	171 pm 147 pm 133 pm 170 pm 176 pm
Metallic Radius	174 pm 197 pm
Ionic Radius	100 pm 106 pm 112 pm 118 pm 123 pm 134 pm
Crystal Radius	114 pm 120 pm 126 pm 132 pm 137 pm 148 pm
Van der Waals Radius	240 pm 231 pm 281 pm 231 pm 339.9 pm
Density	1.54 g/cm³ 1,378 kg/m³
Proton Affinity
Electron Affinity	0.02455 eV/particle
Ionization Energy	6.1131552 eV/particle 11.871718 eV/particle 50.91315 eV/particle 67.2732 eV/particle 84.338 eV/particle 108.78 eV/particle 127.2 eV/particle 147.24 eV/particle 188.535 eV/particle 211.2751 eV/particle 591.6 eV/particle 658.24 eV/particle 728.6 eV/particle 817.22 eV/particle 893.98 eV/particle 973.7 eV/particle 1,086.8 eV/particle 1,157.726 eV/particle 5,128.8576 eV/particle 5,469.8614 eV/particle

Heat of Vaporization	153.6 kJ/mol
Heat of Fusion	9.2 kJ/mol
Heat of Formation	177.8 kJ/mol
Electrons
Electron Shells	2, 8, 8, 2

Valence Electrons	2

Electron Configuration	[Ar] 4s²

Oxidation States	1, 2
Electronegativity	6.113 eV/particle 0.1154119 1
Electrophilicity	0.7734001442996138 eV/particle
Phases
Phase	Solid
Gas Phase
Boiling Point	1,757.15 K
Melting Point	1,115.15 K
Critical Pressure
Critical Temperature
Triple Point
Visual
Color	Silver #808090 #3dff00 #3dff00
Appearance
Refractive Index
Thermodynamic Properties
Thermal Conductivity
Thermal Expansion	0.0000223 1/K
Molar Heat Capacity	25.929 J/(mol K)
Specific Heat Capacity	0.647 J/(g⋅K)
Heat Capacity Ratio (Adiabatic Index)
Electrical Properties
Type	Conductor
Electrical Conductivity	29 MS/m
Electrical Resistivity	0.00000003399999999999 m Ω
Superconducting Point
Magnetism
Type	paramagnetic
Magnetic Susceptibility (Mass)	0.0000000138 m³/Kg
Magnetic Susceptibility (Molar)	0.0000000005531 m³/mol
Magnetic Susceptibility (Volume)	0.00002139
Magnetic Ordering
Curie Point
Neel Point
Structure
Crystal Structure	Face Centered Cubic (FCC)
Lattice Constant	5.58 Å
Lattice Angles	π/2, π/2, π/2
Mechanical Properties
Hardness	167 MPa 1.75 MPa
Bulk Modulus	17 GPa
Shear Modulus	7.4 GPa
Young Modulus	20 GPa
Poisson Ratio	0.31
Speed of Sound	3,810 m/s
Classification
Category	Alkaline earth metals, Alkaline earth metals
CAS Group	IIA
IUPAC Group	IIA
Glawe Number	16
Mendeleev Number	7
Pettifor Number	16
Geochemical Class	major
Goldschmidt Class	litophile
Other
Gas Basicity
Dipole Polarizability	160.8 ± 4 a₀
C6 Dispersion Coefficient	2,163 a₀ 2,230 a₀
Allotropes
Neutron Cross Section	0.43
Neutron Mass Absorption	0.00037
Quantum Numbers	1S0
Space Group	225 (Fm_3m)

Isotopes of Calcium

Stable Isotopes	6
Unstable Isotopes	23
Radioactive Isotopes	22

³³Ca

Abundance
Relative Atomic Mass	33.033312 ± 0.000429 Da
Mass Number	33
G-Factor
Half Life
Spin	5/2
Quadrupole Moment
Discovery Year
Parity	+

³³Ca Decay Modes

Decay Mode	Intensity
p (proton emission)	%

³⁴Ca

Abundance
Relative Atomic Mass	34.015985 ± 0.000322 Da
Mass Number	34
G-Factor	0
Half Life
Spin	0
Quadrupole Moment	0
Discovery Year
Parity	+

³⁴Ca Decay Modes

Decay Mode	Intensity
2p (2-proton emission)	%

³⁵Ca

Abundance	Radioactive ☢️
Relative Atomic Mass	35.005572 ± 0.000215 Da
Mass Number	35
G-Factor
Half Life	25.7 ± 0.2 ms
Spin	1/2
Quadrupole Moment	0
Discovery Year	1985
Parity	+

³⁵Ca Decay Modes

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
β⁺ p (β⁺-delayed proton emission)	95.8%
2p (2-proton emission)	4.2%

³⁶Ca

Abundance	Radioactive ☢️
Relative Atomic Mass	35.993074388 ± 0.000042941 Da
Mass Number	36
G-Factor	0
Half Life	100.9 ± 1.3 ms
Spin	0
Quadrupole Moment	0
Discovery Year	1977
Parity	+

³⁶Ca Decay Modes

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
β⁺ p (β⁺-delayed proton emission)	51.2%

³⁷Ca

Abundance	Radioactive ☢️
Relative Atomic Mass	36.985897849 ± 0.00000068 Da
Mass Number	37
G-Factor
Half Life	181 ± 0.9 ms
Spin	3/2
Quadrupole Moment
Discovery Year	1964
Parity	+

³⁷Ca Decay Modes

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
β⁺ p (β⁺-delayed proton emission)	76.8%

³⁸Ca

Abundance	Radioactive ☢️
Relative Atomic Mass	37.976319223 ± 0.000000208 Da
Mass Number	38
G-Factor	0
Half Life	443.7 ± 0.25 ms
Spin	0
Quadrupole Moment	0
Discovery Year	1966
Parity	+

³⁸Ca Decay Modes

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%

³⁹Ca

Abundance	Radioactive ☢️
Relative Atomic Mass	38.970710811 ± 0.00000064 Da
Mass Number	39
G-Factor	0.68093333333333 ± 0.00010666666666667
Half Life	860.3 ± 0.8 ms
Spin	3/2
Quadrupole Moment	0.038 ± 0.003
Discovery Year	1943
Parity	+

³⁹Ca Decay Modes

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%

⁴⁰Ca

Abundance	96.941 ± 0.156
Relative Atomic Mass	39.96259085 ± 0.000000022 Da
Mass Number	40
G-Factor	0
Half Life
Spin	0
Quadrupole Moment	0
Discovery Year	1922
Parity	+

⁴⁰Ca Decay Modes

Decay Mode	Intensity
2β⁺ (double β⁺ decay)	%

⁴¹Ca

Abundance	Radioactive ☢️
Relative Atomic Mass	40.962277905 ± 0.000000147 Da
Mass Number	41
G-Factor
Half Life	99.4 ± 1.5 ky
Spin	7/2
Quadrupole Moment	-0.0665 ± 0.0018
Discovery Year	1939
Parity	-

⁴¹Ca Decay Modes

Decay Mode	Intensity
ϵ (electron capture)	100%

⁴²Ca

Abundance	0.647 ± 0.023
Relative Atomic Mass	41.95861778 ± 0.000000159 Da
Mass Number	42
G-Factor	0
Half Life
Spin	0
Quadrupole Moment	0
Discovery Year	1934
Parity	+

⁴³Ca

Abundance	0.135 ± 0.01
Relative Atomic Mass	42.958766381 ± 0.000000244 Da
Mass Number	43
G-Factor	-0.37638 ± 0.000017142857142857
Half Life
Spin	7/2
Quadrupole Moment	-0.0408 ± 0.0008
Discovery Year	1934
Parity	-

⁴⁴Ca

Abundance	2.086 ± 0.11
Relative Atomic Mass	43.955481489 ± 0.000000348 Da
Mass Number	44
G-Factor	0
Half Life
Spin	0
Quadrupole Moment	0
Discovery Year	1922
Parity	+

⁴⁵Ca

Abundance	Radioactive ☢️
Relative Atomic Mass	44.95618627 ± 0.000000392 Da
Mass Number	45
G-Factor	-0.37897142857143 ± 0.00037142857142857
Half Life	162.61 ± 0.09 d
Spin	7/2
Quadrupole Moment	0.038 ± 0.012
Discovery Year	1940
Parity	-

⁴⁵Ca Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	100%

⁴⁶Ca

Abundance	0.004 ± 0.003
Relative Atomic Mass	45.953687726 ± 0.000002398 Da
Mass Number	46
G-Factor	0
Half Life
Spin	0
Quadrupole Moment	0
Discovery Year	1938
Parity	+

⁴⁶Ca Decay Modes

Decay Mode	Intensity
2β⁻ (double β⁻ decay)	%

⁴⁷Ca

Abundance	Radioactive ☢️
Relative Atomic Mass	46.954541134 ± 0.000002384 Da
Mass Number	47
G-Factor	-0.40182857142857 ± 0.00031428571428571
Half Life	4.536 ± 0.003 d
Spin	7/2
Quadrupole Moment	0.084 ± 0.006
Discovery Year	1951
Parity	-

⁴⁷Ca Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	100%

⁴⁸Ca

Abundance	Radioactive ☢️ 0.187 ± 0.021
Relative Atomic Mass	47.952522654 ± 0.000000018 Da
Mass Number	48
G-Factor	0
Half Life	56 ± 10 Ey
Spin	0
Quadrupole Moment	0
Discovery Year	1938
Parity	+

⁴⁸Ca Decay Modes

Decay Mode	Intensity
2β⁻ (double β⁻ decay)	%
β⁻ (β⁻ decay)	%

⁴⁹Ca

Abundance	Radioactive ☢️
Relative Atomic Mass	48.955662625 ± 0.00000019 Da
Mass Number	49
G-Factor	-0.91993333333333 ± 0.00053333333333333
Half Life	8.718 ± 0.006 m
Spin	3/2
Quadrupole Moment	-0.036 ± 0.003
Discovery Year	1950
Parity	-

⁴⁹Ca Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	100%

⁵⁰Ca

Abundance	Radioactive ☢️
Relative Atomic Mass	49.957499215 ± 0.0000017 Da
Mass Number	50
G-Factor	0
Half Life	13.45 ± 0.05 s
Spin	0
Quadrupole Moment	0
Discovery Year	1964
Parity	+

⁵⁰Ca Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	100%

⁵¹Ca

Abundance	Radioactive ☢️
Relative Atomic Mass	50.960995663 ± 0.00000056 Da
Mass Number	51
G-Factor	-0.69973333333333 ± 0.00073333333333333
Half Life	10 ± 0.8 s
Spin	3/2
Quadrupole Moment	0.036 ± 0.012
Discovery Year	1980
Parity	-

⁵¹Ca Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	100%
β⁻ n (β⁻-delayed neutron emission)	%

⁵²Ca

Abundance	Radioactive ☢️
Relative Atomic Mass	51.963213646 ± 0.00000072 Da
Mass Number	52
G-Factor	0
Half Life	4.6 ± 0.3 s
Spin	0
Quadrupole Moment	0
Discovery Year	1985
Parity	+

⁵²Ca Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	100%
β⁻ n (β⁻-delayed neutron emission)	2%

⁵³Ca

Abundance	Radioactive ☢️
Relative Atomic Mass	52.968451 ± 0.000047 Da
Mass Number	53
G-Factor
Half Life	461 ± 90 ms
Spin	1/2
Quadrupole Moment	0
Discovery Year	1983
Parity	-

⁵³Ca Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	100%
β⁻ n (β⁻-delayed neutron emission)	40%

⁵⁴Ca

Abundance	Radioactive ☢️
Relative Atomic Mass	53.972989 ± 0.000052 Da
Mass Number	54
G-Factor	0
Half Life	90 ± 6 ms
Spin	0
Quadrupole Moment	0
Discovery Year	1997
Parity	+

⁵⁴Ca Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	100%
β⁻ n (β⁻-delayed neutron emission)	%
2n (2-neutron emission)	%

⁵⁵Ca

Abundance	Radioactive ☢️
Relative Atomic Mass	54.979978 ± 0.000172 Da
Mass Number	55
G-Factor
Half Life	22 ± 2 ms
Spin	5/2
Quadrupole Moment
Discovery Year	1997
Parity	-

⁵⁵Ca Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	100%
β⁻ n (β⁻-delayed neutron emission)	%
2n (2-neutron emission)	%

⁵⁶Ca

Abundance	Radioactive ☢️
Relative Atomic Mass	55.985496 ± 0.000268 Da
Mass Number	56
G-Factor	0
Half Life	11 ± 2 ms
Spin	0
Quadrupole Moment	0
Discovery Year	1997
Parity	+

⁵⁶Ca Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	100%
β⁻ n (β⁻-delayed neutron emission)	%
2n (2-neutron emission)	%

⁵⁷Ca

Abundance	Radioactive ☢️
Relative Atomic Mass	56.992958 ± 0.000429 Da
Mass Number	57
G-Factor
Half Life
Spin	5/2
Quadrupole Moment
Discovery Year	2009
Parity	-

⁵⁷Ca Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	%
β⁻ n (β⁻-delayed neutron emission)	%
2n (2-neutron emission)	%

⁵⁸Ca

Abundance	Radioactive ☢️
Relative Atomic Mass	57.998357 ± 0.000537 Da
Mass Number	58
G-Factor	0
Half Life
Spin	0
Quadrupole Moment	0
Discovery Year	2009
Parity	+

⁵⁸Ca Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	%
β⁻ n (β⁻-delayed neutron emission)	%
2n (2-neutron emission)	%

⁵⁹Ca

Abundance	Radioactive ☢️
Relative Atomic Mass	59.006237 ± 0.000644 Da
Mass Number	59
G-Factor
Half Life
Spin	5/2
Quadrupole Moment
Discovery Year	2018
Parity	-

⁵⁹Ca Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	%
β⁻ n (β⁻-delayed neutron emission)	%
2n (2-neutron emission)	%

⁶⁰Ca

Abundance	Radioactive ☢️
Relative Atomic Mass	60.011809 ± 0.000751 Da
Mass Number	60
G-Factor	0
Half Life
Spin	0
Quadrupole Moment	0
Discovery Year	2018
Parity	+

⁶⁰Ca Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	%
β⁻ n (β⁻-delayed neutron emission)	%
2n (2-neutron emission)	%

⁶¹Ca

Abundance	Radioactive ☢️
Relative Atomic Mass	61.020408 ± 0.000859 Da
Mass Number	61
G-Factor
Half Life
Spin	1/2
Quadrupole Moment	0
Discovery Year
Parity	-

⁶¹Ca Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	%
β⁻ n (β⁻-delayed neutron emission)	%
2n (2-neutron emission)	%

History

Calcium was known as early as the first century when the Ancient Romans prepared lime as calcium oxide. Calcium was first isolated by Sir Humphry Davy in 1808 when he electrolyzed a mixture of lime and mercuric oxide. Davy was trying to isolate calcium; when he heard that Jöns Jakob Berzelius and Pontin prepared calcium amalgam by electrolyzing lime in mercury, he tried it himself. From the Latin word calx, lime

Discoverers	Sir Humphrey Davy
Discovery Location	England
Discovery Year	1808
Etymology (Name Origin)	Latin: calx, calcis (lime).
Pronunciation	KAL-si-em (English)

Calcium is considered to be non-toxic

The shell of an egg is made up of primarily calcium carbonate

Uses

Calcium is used to remove oxygen, sulfur and carbon from alloys. It is also used as an alloying agent used in the production of aluminum, beryllium, copper, lead, and magnesium alloys. Calcium is used as a reducing agent in the extraction of other metals, such as uranium, zirconium, and thorium. Calcium carbonate is used in manufacturing cement and mortar, lime and limestone. 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.

Sources

Obtained from minerals like chalk, limestone & marble. Pure metal is produced by replacing the calcium in lime (calcium carbonate, CaCO3) with aluminium in hot, low pressure retorts.

Abundance
Abundance in Earth's crust	41,500 mg/kg
Abundance in Oceans	412 mg/L
Abundance in Human Body	1.4 %
Abundance in Meteor	1.1 %
Abundance in Sun	0.007 %
Abundance in Universe	0.007 %

Nuclear Screening Constants

1	s	0.527
2	p	3.9586
2	s	6.2236
3	p	11.3417
3	s	10.3985
4	s	15.602

Calcium on ChemicalAid

Art & Architecture Thesaurus ID	300264232
Australian Educational Vocabulary ID	scot/3064
BNCF Thesaurus ID	8953
Basque Vikidia ID	Kaltzio
Biblioteca Nacional de España ID	XX531346
Bibliothèque nationale de France ID	11976285h
Brockhaus Enzyklopädie online ID	calcium-20
CAS Registry Number	7440-70-2
ChEBI ID	22984
ChemSpider ID	4573905
DSSTOX compound identifier	DTXCID40876145
DSSTox substance ID	DTXSID9050484
Den Store Danske ID	calcium
DrugBank ID	01373
ECHA Substance Infocard ID	100.028.344
Encyclopedia of China Online Database ID (Second Edition)	203125
Encyclopædia Britannica Online ID	science/calcium
Encyclopædia Britannica Online ID	science/calcium-ion
Encyclopædia Universalis ID	calcium
EuroVoc ID	5304
Freebase ID	/m/025tkqy
French Vikidia ID	Calcium
GND ID	4069806-3
Gran Enciclopèdia Catalana ID	0087196
Gran Enciclopèdia Catalana ID	0013023
Great Russian Encyclopedia Online ID	2037432
HSDB ID	273
ICSC ID	1192
InChI	InChI=1S/Ca
InChIKey	OYPRJOBELJOOCE-UHFFFAOYSA-N
KBpedia ID	Calcium
KEGG ID	C00076
Latvian National Encyclopedia Online ID	139701
Library of Congress authority ID	sh85018768
MeSH descriptor ID	D002118
NALT ID	6421
NDF-RT ID	N0000146031
NE.se ID	kalcium
NKCR AUT ID	ph116664
Namuwiki ID	칼슘
National Diet Library ID	00565069
National Library of Israel J9U ID	987007293780405171
New York Times topic ID	subject/calcium
OmegaWiki Defined Meaning	471
OpenAlex ID	C2910173204
OpenAlex ID	C519063684
PSH ID	5752
PatientsLikeMe treatment ID	calcium
PubChem CID	5460341
Quora topic ID	Calcium
RxNorm ID	1895
Spanish Vikidia ID	Calcio
Store medisinske leksikon ID	kalsium
Store medisinske leksikon ID	kalsium_-_fysiologi
Store norske leksikon ID	kalsium
Treccani ID	calcio
UK Archival Thesaurus ID	f2/mt225/4347/702
UK Parliament thesaurus ID	8918
UMLS CUI	C0006675
UNESCO Thesaurus ID	concept4508
UNII	SY7Q814VUP
UNSPSC Code	11101511
WordNet 3.1 Synset ID	14656826-n
YSO ID	1852
ZVG number	8160
Zhihu topic ID	19668568

Calcium (Ca)

Properties

Isotopes of Calcium

33Ca

33Ca Decay Modes

34Ca

34Ca Decay Modes

35Ca

35Ca Decay Modes

36Ca

36Ca Decay Modes

37Ca

37Ca Decay Modes

38Ca

38Ca Decay Modes

39Ca

39Ca Decay Modes

40Ca

40Ca Decay Modes

41Ca

41Ca Decay Modes

42Ca

43Ca

44Ca

45Ca

45Ca Decay Modes

46Ca

46Ca Decay Modes

47Ca

47Ca Decay Modes

48Ca

48Ca Decay Modes

49Ca

49Ca Decay Modes

50Ca

50Ca Decay Modes

51Ca

51Ca Decay Modes

52Ca

52Ca Decay Modes

53Ca

53Ca Decay Modes

54Ca

54Ca Decay Modes

55Ca

55Ca Decay Modes

56Ca

56Ca Decay Modes

57Ca

57Ca Decay Modes

58Ca

58Ca Decay Modes

59Ca

59Ca Decay Modes

60Ca

60Ca Decay Modes

61Ca

61Ca Decay Modes