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Actinium

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Actinium Quick Reference

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Notes

Symbol

Ac

Atomic Number

89

Oxidation States

3

Pauling Electronegativity

1.1

Electron Configuration

Orbital Occupancy

[Rn] 6d1 7s2

[Rn] represents the closed-shell electron configuration of radon

Orbital Filling Order

[Rn] 7s2 6d1

[Rn] represents the closed-shell electron configuration of radon

Term Symbol

2D3/2

see expanded configuration ...

Ionization Energies

I  (1)

 5.17 eV

II (2)

11.75 eV

Electron Affinity

0.35 eV

Density

solid, 25 °C

10.000 g/cm3

Molar Volume

solid, 298 K, 1 atm

22.554 cm3/mol

Melting Point

1323 ± 50 K

Boiling Point

1 atm

3471.15 K

Thermal Conductivity

solid, 300 K

11.5 W/(m K)

derived value

Pyykkö Covalent Radius

single bond

186 pm

double bond

153 pm

triple bond

140 pm

Enthalpy of Fusion

1 atm

14.2 kJ/mol

Enthalpy of Vaporization

1 atm

293 kJ/mol

Quantity

Actinium Atomic Structure

Notes

Ionization Energies

I  (1)

 5.17 eV

II (2)

11.75 eV

Electron Affinity

0.35 eV

Electron Binding Energies

K    (1s)

106755 eV

LI   (2s)

 19840 eV

LII  (2p1/2)

 19083 eV

LIII (2p3/2)

 15871 eV

see all 21 energies ...

Electron Configuration

Orbital Occupancy

[Rn] 6d1 7s2

[Rn] represents the closed-shell electron configuration of radon

Orbital Filling Order

[Rn] 7s2 6d1

[Rn] represents the closed-shell electron configuration of radon

Term Symbol

2D3/2

see expanded configuration ...

Fluorescence Yields

ωK

0.969

ωL1

0.154

ωL2

0.49 

ωL3

0.414

Coster-Kronig Yields

F12

0.044

F13

0.62 

F23

0.105

Quantity

Actinium Physical Properties

Notes

Density

solid, 25 °C

10.000 g/cm3

Molar Volume

solid, 298 K, 1 atm

22.554 cm3/mol

Physical Form

silvery metal

Young's Modulus

25.0 GPa

Isothermal Bulk Modulus

300 K

25 GPa

estimated

Isothermal Compressibility

300 K

0.04 GPa-1

estimated

Quantity

Actinium Atomic Interaction

Notes

Oxidation States

3

Pauling Electronegativity

1.1

Allred-Rochow Electronegativity

1.00

Nagle Electronegativity

1.03

Cohesive Energy

per mole

410 kJ/mol    

per atom

  4.25 eV/atom

Quantity

Actinium Thermodynamics

Notes

Melting Point

1323 ± 50 K

Boiling Point

1 atm

3471.15 K

Thermal Conductivity

solid, 300 K

11.5 W/(m K)

derived value

Critical Point

16270 K

Enthalpy of Fusion

1 atm

14.2 kJ/mol

Enthalpy of Vaporization

1 atm

293 kJ/mol

Isobaric Molar Heat Capacity

298.15 K, 1 bar

27.2 J/(mol K)

Isobaric Specific Heat Capacity

298.15 K, 1 bar

0.120 J/(g K)

Quantity

Actinium Identification

Notes

CAS Number

7440-34-8

Quantity

Actinium Atomic Size

Notes

Orbital Radius

189.5 pm

Pyykkö Covalent Radius

single bond

186 pm

double bond

153 pm

triple bond

140 pm

Cordero Covalent Radius

215 pm

Shannon-Prewitt Crystal Radius

ion charge: +3, coordination number: 6

126 pm

Shannon-Prewitt Effective Ionic Radius

ion charge: +3, coordination number: 6

112 pm

Pauling Empirical Crystal Radius

ion charge: +3

118 pm

Slater Atomic-Ionic Radius

195 pm

Quantity

Actinium Crystal Structure

Notes

Nearest Neighbor Distance

300 K, 1 atm

376 pm

Atomic Concentration

300 K, 1 atm

2.66×1022 cm-3

Quantity

Actinium History

Notes

Discovery

date of discovery

1899

discoverer

André Louis Debierne

birth

1874

death

1949

location of discovery

Paris, France

Origin of Element Name

origin

aktinos

origin description

property—Greek for ray

Origin of Element Symbol

symbol: Ac

origin

actinium

origin description

element name

Formerly Used or Proposed Element Names and Symbols

name

emanium

no matching symbol specified

Quantity

Actinium Abundances

Notes

Earth's Crust

5.5×10-10 ppm

Quantity

Actinium Nomenclature

Notes

Element Names in Other Languages

French

actinium

German

Actinium

Italian

attinio

Spanish

actinio

Portuguese

actínio

Anions or Anionic Substituent Groups

actinide

Cations or Cationic Substituent Groups

actinium

Ligands

actinido

Heteroatomic Anion

actinate

'a' Term—Substitutive Nomenclature

actina

'y' Term—Chains and Rings Nomenclature

actiny

References    (Click the button next to a value above to see complete citation information for that entry)

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