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Calcium Quick Reference

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Notes

Symbol

Ca

Atomic Number

20

Atomic Weight

Rounded

40.08

for regular calculations

Standard

40.078 ± 0.004

for precise calculations

Oxidation States

2

Pauling Electronegativity

1.00

Electron Configuration

Orbital Occupancy

[Ar] 4s2

[Ar] represents the closed-shell electron configuration of argon

Orbital Filling Order

[Ar] 4s2

[Ar] represents the closed-shell electron configuration of argon

Term Symbol

1S0

see expanded configuration ...

Ionization Energies

I   (1)

 6.11316 eV        

II  (2)

11.87172 eV        

III (3)

50.9135 ± 0.0002 eV

IV  (4)

67.27 ± 0.13 eV    

see all 20 energies ...

Electron Affinity

0.02455 ± 0.00010 eV

  198.0 ± 0.8 cm-1  

Density

liquid, 1115.00 K

1.368 g/ml 

solid, 25 °C

1.540 g/cm3

Molar Volume

solid, 298 K, 1 atm

26.20 cm3/mol

Melting Point

1 bar

1115 ± 2 K

Boiling Point

1 atm

1757.00 K

Thermal Conductivity

solid

400 K

188 W/(m K)

estimated

300 K

200 W/(m K)

estimated

298.2 K

201 W/(m K)

estimated

273.2 K

206 W/(m K)

estimated

200 K

222 W/(m K)

estimated

see all 23 conductivities ...

Pyykkö Covalent Radius

single bond

171 pm

double bond

147 pm

triple bond

133 pm

Atomic Radius

197 pm

Enthalpy of Fusion

1 atm

9.33 kJ/mol

Enthalpy of Vaporization

1 atm

149.95 kJ/mol

Quantity

Calcium Atomic Structure

Notes

Ionization Energies

I   (1)

 6.11316 eV        

II  (2)

11.87172 eV        

III (3)

50.9135 ± 0.0002 eV

IV  (4)

67.27 ± 0.13 eV    

see all 20 energies ...

Electron Affinity

0.02455 ± 0.00010 eV

  198.0 ± 0.8 cm-1  

Electron Binding Energies

K    (1s)

4038.5 eV

LI   (2s)

 438.4 eV

LII  (2p1/2)

 349.7 eV

LIII (2p3/2)

 346.2 eV

see all 7 energies ...

Electron Configuration

Orbital Occupancy

[Ar] 4s2

[Ar] represents the closed-shell electron configuration of argon

Orbital Filling Order

[Ar] 4s2

[Ar] represents the closed-shell electron configuration of argon

Term Symbol

1S0

see expanded configuration ...

Clementi-Raimondi Effective Nuclear Charge

1s

Orbital Exponent

19.4730

ζ

Principle Quantum Number

1

n

Effective Nuclear Charge

19.4730

Zeff = ζ × n

2s

Orbital Exponent

 6.8882

ζ

Principle Quantum Number

2

n

Effective Nuclear Charge

13.776 

Zeff = ζ × n

see all 6 effective nuclear charges ...

Screening Percentage

85.8%

Fluorescence Yields

ωK

0.169  

ωL1

0.00031

ωL2

0.00033

ωL3

0.00033

Coster-Kronig Yields

F12

0.31

F13

0.61

Quantity

Calcium Physical Properties

Notes

Density

liquid, 1115.00 K

1.368 g/ml 

solid, 25 °C

1.540 g/cm3

Molar Mass

Rounded

40.08 g/mol

for regular calculations

Standard

40.078 ± 0.004 g/mol

for precise calculations

Molar Volume

solid, 298 K, 1 atm

26.20 cm3/mol

Physical Form

silvery-white metal

Linear Thermal Expansion Coefficient

25 °C

22.3×10-6 K-1

Speed of Sound

α-calcium, solid, 293 K

3560 m/s to 4060 m/s

Young's Modulus

α-calcium

19.6 GPa

Poisson's Ratio

α-calcium

0.310

Dielectric Constant

3.0

Electrical Resistivity

solid

200 K

2.19×10-8 Ohm m

273.15 K

3.11×10-8 Ohm m

293 K

3.36×10-8 Ohm m

300 K

3.45×10-8 Ohm m

400 K

4.73×10-8 Ohm m

see all 47 resistivities ...

Contact Potential

3.33 eV

Photoelectric Work Function

2.706 eV

Thermionic Work Function

2.24 eV

Superconducting Transition Temperature

161 GPa

25 K

maximum temperature

Mineralogical Hardness

1.75

Isothermal Bulk Modulus

300 K

15.2 GPa

Isothermal Compressibility

300 K

0.0658 GPa-1

Gram Atomic Volume

26 cm3

Quantity

Calcium Atomic Interaction

Notes

Oxidation States

2

Pauling Electronegativity

1.00

Mulliken-Jaffe Electronegativity

hybridsp

1.08

Sanderson Electronegativity

oxidation state: 2

0.95

oxidation state: 1

1.13

Allred-Rochow Electronegativity

1.04

Configuration Energy

electron volt units

6.113 eV

Pauling units

1.034   

Allen Electronegativity

1.034

Allred Electronegativity

oxidation state: 2

1.00

Boyd-Edgecombe Electronegativity

1.34

Ghosh-Gupta Electronegativity

2.6965 eV

Nagle Electronegativity

1.11

Pearson Absolute Electronegativity

2.2 eV

Smith Electronegativity

oxidation state: 2

1.05

Free Electron Fermi Surface Parameters

300 K

electron concentration

4.60×1022 cm-3

radius parameter

3.27

fermi wavevector

1.11×108 cm-1

fermi velocity

1.28×108 cm/s

fermi energy

4.68 eV

fermi temperature

5.43×104 K

Chemical Hardness

4.0 eV

Cohesive Energy

per mole

178 kJ/mol    

per atom

  1.84 eV/atom

Quantity

Calcium Thermodynamics

Notes

Melting Point

1 bar

1115 ± 2 K

Boiling Point

1 atm

1757.00 K

Thermal Conductivity

solid

400 K

188 W/(m K)

estimated

300 K

200 W/(m K)

estimated

298.2 K

201 W/(m K)

estimated

273.2 K

206 W/(m K)

estimated

200 K

222 W/(m K)

estimated

see all 23 conductivities ...

Critical Point

2880 K

Vapor Pressure

1482 °C

100 kPa

1170 °C

10 kPa

954 °C

1 kPa

see all 15 pressures ...

Enthalpy of Fusion

1 atm

9.33 kJ/mol

Enthalpy of Vaporization

1 atm

149.95 kJ/mol

Isobaric Molar Heat Capacity

298.15 K, 1 bar

25.929 J/(mol K)

Isobaric Specific Heat Capacity

298.15 K, 1 bar

0.647 J/(g K)

Electronic Heat Capacity Coefficient

2.73 mJ/(mol K2)

Debye Temperature

Low Temperature Limit ( 0 K )

229 K

Room Temperature ( 298 K )

230 K

Quantity

Calcium Identification

Notes

CAS Number

7440-70-2

DOT Number

1401

pyrophoric

1855

ICSC Number

1192

RTECS Number

EV8040000

UN Number

1401

Quantity

Calcium Atomic Size

Notes

Atomic Radius

197 pm

Orbital Radius

169.0 pm

Pyykkö Covalent Radius

single bond

171 pm

double bond

147 pm

triple bond

133 pm

Cordero Covalent Radius

176 pm

Shannon-Prewitt Crystal Radius

ion charge: +2

coordination number: 6

114 pm

coordination number: 7

120 pm

coordination number: 8

126 pm

coordination number: 9

132 pm

coordination number: 10

137 pm

coordination number: 12

148 pm

Shannon-Prewitt Effective Ionic Radius

ion charge: +2

coordination number: 6

100 pm

coordination number: 7

106 pm

coordination number: 8

112 pm

coordination number: 9

118 pm

coordination number: 10

123 pm

coordination number: 12

134 pm

Pauling Empirical Crystal Radius

ion charge: +2

99 pm

Pauling Univalent Radius

ion charge: +1

118 pm

Batsanov Crystallographic Van Der Waals Radius

2.4×102 pm

Batsanov Equilibrium Van Der Waals Radius

278 pm

Slater Atomic-Ionic Radius

180 pm

Quantity

Calcium Crystal Structure

Notes

Allotropes

allotrope

α-calcium

symbol

αCa

allotrope

β-calcium

symbol

βCa

Nearest Neighbor Distance

300 K, 1 atm

395 pm

Atomic Concentration

300 K, 1 atm

2.30×1022 cm-3

Quantity

Calcium History

Notes

Discovery

date of discovery

1808

discoverer

Humphry Davy

birth

December 17, 1778

death

May 29, 1829

location of discovery

London, England

Origin of Element Name

origin

calx

origin description

mineral—Latin for lime or chalk

Origin of Element Symbol

symbol: Ca

origin

calcium

origin description

element name

U.S. Towns Named After Elements

Calcium, New York

Quantity

Calcium Abundances

Notes

Earth's Crust

4.15×104 ppm

Earth's Mantle

26100 ppm

primitive mantle

Bulk Earth

1.71%

Ocean Water

4.22 ppm

Metalliferous Ocean Sediment

Basal

1.47%

River Water

1.5 ppm

U.S. Coal

0.46%

Human Body

1.00 kg

based on a 70 kg "reference man"

Human Bone

170×103 ppm

Human Hair

150 ppm to 3200 ppm

Human Kidney

360 ppm to 820 ppm

Human Liver

100 ppm to 360 ppm

Human Muscle

140 ppm to 700 ppm

Human Nail

370 ppm to 3400 ppm

Bacteria

5.1×103 ppm

Ferns

3.7×103 ppm

Fungi

0.2 ppm to 1.7×103 ppm

Solar System

6.11×104

number of atoms for every 106 atoms of silicon

Sun

6.36 ± 0.02

base 10 log of the number of atoms for every 1012 atoms of hydrogen

Moon

Terrae

6.1 ± 0.6 %

Maria

4.7 ± 0.4 %

Average

5.8%

Meteorites

6.35 ± 0.01

base 10 log of the number of atoms for every 1012 atoms of hydrogen

Halley's Comet

6.3 ± 1.9 atoms

number of atoms for every 100 atoms of magnesium

Quantity

Calcium Nomenclature

Notes

Element Names in Other Languages

French

calcium

German

Calcium

Italian

calcio

Spanish

calcio

Portuguese

cálcio

Anions or Anionic Substituent Groups

calcide

Cations or Cationic Substituent Groups

calcium (general)

Ca2+, calcium(2+)

Ligands

calcido

Heteroatomic Anion

calcate

'a' Term—Substitutive Nomenclature

calca

'y' Term—Chains and Rings Nomenclature

calcy

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