Americium

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Americium Quick Reference

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Notes

Symbol

Am

Atomic Number

95

Oxidation States

7

unverified

6

less common

5

less common

4

less common

3

more common

2

less common

Pauling Electronegativity

1.3

Electron Configuration

Orbital Occupancy

[Rn] 5f7 7s2

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

Orbital Filling Order

[Rn] 7s2 5f7

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

Term Symbol

8S7/2

see expanded configuration ...

Ionization Energies

I (1)

5.9738 eV

Density

solid, 25 °C

12.000 g/cm3

Molar Volume

solid, 298 K, 1 atm

17.63 cm3/mol

Melting Point

1449 ± 5 K

Boiling Point

1 atm

2284.15 K

Thermal Conductivity

solid, 300 K

10 W/(m K)

estimated

Pyykkö Covalent Radius

single bond

166 pm

double bond

135 pm

Atomic Radius

140 pm

Enthalpy of Fusion

1 atm

14.4 kJ/mol

Enthalpy of Vaporization

1 atm

238.5 kJ/mol

Quantity

Americium Atomic Structure

Notes

Ionization Energies

I (1)

5.9738 eV

Electron Binding Energies

K    (1s)

124982 ± 5 eV

LI   (2s)

 23808 ± 3 eV

LII  (2p1/2)

 22952 ± 3 eV

LIII (2p3/2)

 18510 ± 3 eV

see all 24 energies ...

Electron Configuration

Orbital Occupancy

[Rn] 5f7 7s2

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

Orbital Filling Order

[Rn] 7s2 5f7

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

Term Symbol

8S7/2

see expanded configuration ...

Fluorescence Yields

ωK

0.971

ωL1

0.22 

ωL2

0.487

ωL3

0.473

Coster-Kronig Yields

F12

0.03 

F13

0.68 

F23

0.222

Quantity

Americium Physical Properties

Notes

Density

solid, 25 °C

12.000 g/cm3

Molar Volume

solid, 298 K, 1 atm

17.63 cm3/mol

Physical Form

silvery metal

Superconducting Transition Temperature

ambient pressure

0.79 K

6 GPa

2.2 K 

maximum temperature

α-americium

0.6 K 

β-americium

1.0 K 

Quantity

Americium Atomic Interaction

Notes

Oxidation States

7

unverified

6

less common

5

less common

4

less common

3

more common

2

less common

Pauling Electronegativity

1.3

Allred-Rochow Electronegativity

1.2

Nagle Electronegativity

1.10

Cohesive Energy

per mole

264 kJ/mol    

per atom

  2.73 eV/atom

Quantity

Americium Thermodynamics

Notes

Melting Point

1449 ± 5 K

Boiling Point

1 atm

2284.15 K

Thermal Conductivity

solid, 300 K

10 W/(m K)

estimated

Critical Point

10800 K

Enthalpy of Fusion

1 atm

14.4 kJ/mol

Enthalpy of Vaporization

1 atm

238.5 kJ/mol

Electronic Heat Capacity Coefficient

27 mJ/(mol K2)

Debye Temperature

Low Temperature Limit ( 0 K )

121 K

Quantity

Americium Identification

Notes

CAS Number

7440-35-9

Quantity

Americium Atomic Size

Notes

Atomic Radius

140 pm

Orbital Radius

175.7 pm

Pyykkö Covalent Radius

single bond

166 pm

double bond

135 pm

Cordero Covalent Radius

180 pm

Shannon-Prewitt Crystal Radius

ion charge: +2

coordination number: 7

135 pm  

coordination number: 8

140 pm  

coordination number: 9

145 pm  

ion charge: +3

coordination number: 6

111.5 pm

coordination number: 8

123 pm  

ion charge: +4

coordination number: 6

 99 pm  

coordination number: 8

109 pm  

Shannon-Prewitt Effective Ionic Radius

ion charge: +2

coordination number: 7

121 pm  

coordination number: 8

126 pm  

coordination number: 9

131 pm  

ion charge: +3

coordination number: 6

 97.5 pm

coordination number: 8

109 pm  

ion charge: +4

coordination number: 6

 85 pm  

coordination number: 8

 95 pm  

Pauling Empirical Crystal Radius

ion charge: +4

 92 pm

ion charge: +3

106 pm

Slater Atomic-Ionic Radius

175 pm

Quantity

Americium Crystal Structure

Notes

Allotropes

allotrope

α'-americium

symbol

α'Am

alternate symbol

αAm

allotrope

α-americium

symbol

αAm

alternate symbol

βAm

allotrope

β-americium

symbol

βAm

alternate symbol

γAm

allotrope

γ-americium

symbol

γAm

Nearest Neighbor Distance

300 K, 1 atm

361 pm

Atomic Concentration

300 K, 1 atm

2.96×1022 cm-3

Quantity

Americium History

Notes

Discovery

date of discovery

1944

discoverer

Glenn Theodore Seaborg

birth

April 19, 1912

death

February 25, 1999

discoverer

Ralph A. James

discoverer

Leon O. Morgan

location of discovery

Metallurgical Laboratory, Chicago, Illinois

Origin of Element Name

origin

America

origin description

place

Origin of Element Symbol

symbol: Am

origin

americium

origin description

element name

Quantity

Americium Nomenclature

Notes

Element Names in Other Languages

French

américium

German

Americium

Italian

americio

Spanish

americio

Portuguese

amerício

Anions or Anionic Substituent Groups

americide

Cations or Cationic Substituent Groups

americium

Ligands

americido

Heteroatomic Anion

americate

'a' Term—Substitutive Nomenclature

america

'y' Term—Chains and Rings Nomenclature

americy

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

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