Actinium is a soft, silvery-white radioactive metal which reacts rapidly with oxygen and moisture in the air forming a white coating of actinium oxide that prevents further oxidation. Found only in traces in uranium and thorium ores as the isotope 227Ac, which decays with a half-life of 21.772 years, predominantly emitting beta and sometimes alpha particles, and 228Ac, which is beta active with a half-life of 6.15 hours. One tonne of natural uranium in ore contains about 0.2 milligrams of actinium-227, and one tonne of natural thorium contains about 5 nanograms of actinium-228.

Actinium is a soft, silvery-white radioactive metal which reacts rapidly with oxygen and moisture in the air forming a white coating of actinium oxide that prevents further oxidation. Found only in traces in uranium and thorium ores as the isotope 227Ac, which decays with a half-life of 21.772 years, predominantly emitting beta and sometimes alpha particles, and 228Ac, which is beta active with a half-life of 6.15 hours. One tonne of natural uranium in ore contains about 0.2 milligrams of actinium-227, and one tonne of natural thorium contains about 5 nanograms of actinium-228.

Actinium is a soft, silvery-white radioactive metal which reacts rapidly with oxygen and moisture in the air forming a white coating of actinium oxide that prevents further oxidation. Found only in traces in uranium and thorium ores as the isotope 227Ac, which decays with a half-life of 21.772 years, predominantly emitting beta and sometimes alpha particles, and 228Ac, which is beta active with a half-life of 6.15 hours. One tonne of natural uranium in ore contains about 0.2 milligrams of actinium-227, and one tonne of natural thorium contains about 5 nanograms of actinium-228.

Actinium is a soft, silvery-white radioactive metal which reacts rapidly with oxygen and moisture in the air forming a white coating of actinium oxide that prevents further oxidation. Found only in traces in uranium and thorium ores as the isotope 227Ac, which decays with a half-life of 21.772 years, predominantly emitting beta and sometimes alpha particles, and 228Ac, which is beta active with a half-life of 6.15 hours. One tonne of natural uranium in ore contains about 0.2 milligrams of actinium-227, and one tonne of natural thorium contains about 5 nanograms of actinium-228.

Actinium is a soft, silvery-white radioactive metal which reacts rapidly with oxygen and moisture in the air forming a white coating of actinium oxide that prevents further oxidation. Found only in traces in uranium and thorium ores as the isotope 227Ac, which decays with a half-life of 21.772 years, predominantly emitting beta and sometimes alpha particles, and 228Ac, which is beta active with a half-life of 6.15 hours. One tonne of natural uranium in ore contains about 0.2 milligrams of actinium-227, and one tonne of natural thorium contains about 5 nanograms of actinium-228.

---

1899 by Andre-Louis Debierne, France.

1899 by Andre-Louis Debierne, France.

1899 by Andre-Louis Debierne, France.

1899 by Andre-Louis Debierne, France.

1899 by Andre-Louis Debierne, France.

DISCOVERY

DISCOVERY

DISCOVERY

DISCOVERY

DISCOVERY

---

Greek 'aktinos' meaning 'ray'.

Greek 'aktinos' meaning 'ray'.

Greek 'aktinos' meaning 'ray'.

Greek 'aktinos' meaning 'ray'.

Greek 'aktinos' meaning 'ray'.

ETYMOLOGY

ETYMOLOGY

ETYMOLOGY

ETYMOLOGY

ETYMOLOGY

---

---

Actinium

Actinium

Actinium

Actinium

Actinium

---

Element

Element

Element

Element

Element

---

Ac

Ac

Ac

Ac

Ac

---

Symbol

Symbol

Symbol

Symbol

Symbol

---

---

---

89

89

89

89

89

---

Atomic Number

Atomic Number

Atomic Number

Atomic Number

Atomic Number

---

Actinide

Actinide

Actinide

Actinide

Actinide

---

Classification

Classification

Classification

Classification

Classification

---

7440-34-8

7440-34-8

7440-34-8

7440-34-8

7440-34-8

---

CAS Number

CAS Number

CAS Number

CAS Number

CAS Number

---

Silver

Silver

Silver

Silver

Silver

---

Elemental Colour

Elemental Colour

Elemental Colour

Elemental Colour

Elemental Colour

---

-

-

-

-

-

---

Refractive Index

Refractive Index

Refractive Index

Refractive Index

Refractive Index

---

-

-

-

-

-

---

Poisson Ratio

Poisson Ratio

Poisson Ratio

Poisson Ratio

Poisson Ratio

---

22.545 cm³

22.545 cm³

22.545 cm³

22.545 cm³

22.545 cm³

---

Molar Volume

Molar Volume

Molar Volume

Molar Volume

Molar Volume

---

-

-

-

-

-

---

Brinell Hardness

Brinell Hardness

Brinell Hardness

Brinell Hardness

Brinell Hardness

---

-

-

-

-

-

---

Mohs Hardness

Mohs Hardness

Mohs Hardness

Mohs Hardness

Mohs Hardness

---

-

-

-

-

-

---

Vickers Hardness

Vickers Hardness

Vickers Hardness

Vickers Hardness

Vickers Hardness

---

-

-

-

-

-

---

Speed of Sound

Speed of Sound

Speed of Sound

Speed of Sound

Speed of Sound

---

-

-

-

-

-

---

Bulk Modulus

Bulk Modulus

Bulk Modulus

Bulk Modulus

Bulk Modulus

---

-

-

-

-

-

---

Shear Modulus

Shear Modulus

Shear Modulus

Shear Modulus

Shear Modulus

---

-

-

-

-

-

---

Young Modulus

Young Modulus

Young Modulus

Young Modulus

Young Modulus

---

---

---

Allotropes

Allotropes

Allotropes

Allotropes

Allotropes

---

NONE

NONE

NONE

NONE

NONE

---

---

1,323.15 K, 1,050.00 °C

1,323.15 K, 1,050.00 °C

1,323.15 K, 1,050.00 °C

1,323.15 K, 1,050.00 °C

1,050.00 °C

---

Melting Point

Melting Point

Melting Point

Melting Point

Melting Point

---

3,473.15 K, 3,200.00 °C

3,473.15 K, 3,200.00 °C

3,473.15 K, 3,200.00 °C

3,473.15 K, 3,200.00 °C

3,200.00 °C

---

Boiling Point

Boiling Point

Boiling Point

Boiling Point

Boiling Point

---

-

-

-

-

-

---

Automatic Ignition

Automatic Ignition

Automatic Ignition

Automatic Ignition

Automatic Ignition

---

-

-

-

-

-

---

Flashpoint

Flashpoint

Flashpoint

Flashpoint

Flashpoint

---

-

-

-

-

-

---

Critical Temperature

Critical Temperature

Critical Temperature

Critical Temperature

Critical Temperature

---

-

-

-

-

-

---

Critical Pressure

Critical Pressure

Critical Pressure

Critical Pressure

Critical Pressure

---

12.000'000 W/(m K)

12.000'000 W/(m K)

12.000'000 W/(m K)

12.000'000 W/(m K)

12.000'000 W/(m K)

---

Thermal Conductivity

Thermal Conductivity

Thermal Conductivity

Thermal Conductivity

Thermal Conductivity

---

-

-

-

-

-

---

Thermal Expansion

Thermal Expansion

Thermal Expansion

Thermal Expansion

Thermal Expansion

---

120.00 J/(kg K)

120.00 J/(kg K)

120.00 J/(kg K)

120.00 J/(kg K)

120.00 J/(kg K)

---

Specific Heat

Specific Heat

Specific Heat

Specific Heat

Specific Heat

---

14.000 kJ/mol

14.000 kJ/mol

14.000 kJ/mol

14.000 kJ/mol

14.000 kJ/mol

---

Heat Fusion

Heat Fusion

Heat Fusion

Heat Fusion

Heat Fusion

---

400.000 kJ/mol

400.000 kJ/mol

400.000 kJ/mol

400.000 kJ/mol

400.000 kJ/mol

---

Heat Vaporisation

Heat Vaporisation

Heat Vaporisation

Heat Vaporisation

Heat Vaporisation

---

-

-

-

-

-

---

Heat Combustion

Heat Combustion

Heat Combustion

Heat Combustion

Heat Combustion

---

-

-

-

-

-

---

Curie Point

Curie Point

Curie Point

Curie Point

Curie Point

---

-

-

-

-

-

---

Neel Point

Neel Point

Neel Point

Neel Point

Neel Point

---

-

-

-

-

-

---

Adiabatic Index

Adiabatic Index

Adiabatic Index

Adiabatic Index

Adiabatic Index

---

Solid

Solid

Solid

Solid

Solid

---

Phase

Phase

Phase

Phase

Phase

-

-

-

-

-

---

Electrical Type

Electrical Type

Electrical Type

Electrical Type

Electrical Type

---

-

-

-

-

-

---

Conductivity

Conductivity

Conductivity

Conductivity

Conductivity

---

-

-

-

-

-

---

Resistivity

Resistivity

Resistivity

Resistivity

Resistivity

---

-

-

-

-

-

---

Superconducting Point

Superconducting Point

Superconducting Point

Superconducting Point

Superconducting Point

---

-

-

-

-

-

---

Magnetic Type

Magnetic Type

Magnetic Type

Magnetic Type

Magnetic Type

---

-

-

-

-

-

---

Mass Susceptibility

Mass Susceptibility

Mass Susceptibility

Mass Susceptibility

Mass Susceptibility

---

-

-

-

-

-

---

Molar Susceptibility

Molar Susceptibility

Molar Susceptibility

Molar Susceptibility

Molar Susceptibility

---

-

-

-

-

-

---

Volume Susceptibility

Volume Susceptibility

Volume Susceptibility

Volume Susceptibility

Volume Susceptibility

Material Composition

Material Composition

Material Composition

Material Composition

Material Composition

---

-

-

-

-

-

---

Universe

Universe

Universe

Universe

Universe

---

-

-

-

-

-

---

Meteorites

Meteorites

Meteorites

Meteorites

Meteorites

---

-

-

-

-

-

---

Sun

Sun

Sun

Sun

Sun

---

-

-

-

-

-

---

Earth Crust

Earth Crust

Earth Crust

Earth Crust

Earth Crust

---

-

-

-

-

-

---

Oceans

Oceans

Oceans

Oceans

Oceans

---

-

-

-

-

-

---

Humans

Humans

Humans

Humans

Humans

227.027'752'3

227.027'752'3

227.027'752'3

227.027'752'3

227.027'752'3

---

Atomic Weight

Atomic Weight

Atomic Weight

Atomic Weight

Atomic Weight

---

-

-

-

-

-

---

Atomic Radius

Atomic Radius

Atomic Radius

Atomic Radius

Atomic Radius

---

186 pm

186 pm

186 pm

186 pm

186 pm

---

Covalent Radius Single Bond

Covalent Radius Single Bond

Covalent Radius Single Bond

Covalent Radius Single Bond

Covalent Radius Single Bond

---

153 pm

153 pm

153 pm

153 pm

153 pm

---

Covalent Radius Double Bond

Covalent Radius Double Bond

Covalent Radius Double Bond

Covalent Radius Double Bond

Covalent Radius Double Bond

---

140 pm

140 pm

140 pm

140 pm

140 pm

---

Covalent Radius Triple Bond

Covalent Radius Triple Bond

Covalent Radius Triple Bond

Covalent Radius Triple Bond

Covalent Radius Triple Bond

---

260 pm

260 pm

260 pm

260 pm

260 pm

---

Van der Waals Radius

Van der Waals Radius

Van der Waals Radius

Van der Waals Radius

Van der Waals Radius

---

[Rn]7s²6d¹

[Rn]7s²6d¹

[Rn]7s²6d¹

[Rn]7s²6d¹

[Rn]7s²6d¹

---

Electron Configuration

Electron Configuration

Electron Configuration

Electron Configuration

Electron Configuration

---

Cubic, Face-centred

Cubic, Face-centred

Cubic, Face-centred

Cubic, Face-centred

Cubic, Face-centred

---

Crystal Structure

Crystal Structure

Crystal Structure

Crystal Structure

Crystal Structure

---

10.070'00 g/cm³

10.070'00 g/cm³

10.070'00 g/cm³

10.070'00 g/cm³

10.070'00 g/cm³

---

Density as Solid

Density as Solid

Density as Solid

Density as Solid

Density as Solid

---

-

-

-

-

-

---

Density as Liquid

Density as Liquid

Density as Liquid

Density as Liquid

Density as Liquid

---

-

-

-

-

-

---

Density as Gas

Density as Gas

Density as Gas

Density as Gas

Density as Gas

---

Fm_3m

Fm_3m

Fm_3m

Fm_3m

Fm_3m

---

Space Group Name

Space Group Name

Space Group Name

Space Group Name

Space Group Name

---

225

225

225

225

225

---

Space Group Number

Space Group Number

Space Group Number

Space Group Number

Space Group Number

---

π/2, π/2 & π/2

π/2, π/2 & π/2

π/2, π/2 & π/2

π/2, π/2 & π/2

π/2, π/2 & π/2

---

Lattice Angles

Lattice Angles

Lattice Angles

Lattice Angles

Lattice Angles

---

567, 567 & 567 pm

567, 567 & 567 pm

567, 567 & 567 pm

567, 567 & 567 pm

567, 567 & 567 pm

---

Lattice Constants

Lattice Constants

Lattice Constants

Lattice Constants

Lattice Constants

3

3

3

3

3

---

Valence

Valence

Valence

Valence

Valence

---

1.1

1.1

1.1

1.1

1.1

---

Electronegativity

Electronegativity

Electronegativity

Electronegativity

Electronegativity

---

-

-

-

-

-

---

Electron Affinity

Electron Affinity

Electron Affinity

Electron Affinity

Electron Affinity

---

---

---

Ionisation Energy

Ionisation Energy

Ionisation Energy

Ionisation Energy

Ionisation Energy

---

---

---

21.79 years

21.79 years

21.79 years

21.79 years

21.79 years

---

Half Life

Half Life

Half Life

Half Life

Half Life

---

31.43 years

31.43 years

31.43 years

31.43 years

31.43 years

---

Lifetime

Lifetime

Lifetime

Lifetime

Lifetime

---

6d¹ = 6, 2, -2, +1/2

6d¹ = 6, 2, -2, +1/2

6d¹ = 6, 2, -2, +1/2

6d¹ = 6, 2, -2, +1/2

6d¹ = 6, 2, -2, +1/2

---

Quantum Numbers

Quantum Numbers

Quantum Numbers

Quantum Numbers

Quantum Numbers

---

-

-

-

-

-

---

Neutron Cross Section

Neutron Cross Section

Neutron Cross Section

Neutron Cross Section

Neutron Cross Section

---

-

-

-

-

-

---

Neutron Mass Absorption

Neutron Mass Absorption

Neutron Mass Absorption

Neutron Mass Absorption

Neutron Mass Absorption

---

---

---

Stable Isotopes

Stable Isotopes

Stable Isotopes

Stable Isotopes

Stable Isotopes

---

NONE

NONE

NONE

NONE

NONE

---

---

---

Unstable Isotopes

Unstable Isotopes

Unstable Isotopes

Unstable Isotopes

Unstable Isotopes

---

---

---

---

Isotopes Overview

Isotopes Overview

Isotopes Overview

Isotopes Overview

Isotopes Overview

---

---

---