Actinium

Actinium is a chemical element with the symbol Ac and atomic number 89. It is a soft, silvery-white, radioactive metal that glows in the dark. Actinium was discovered in 1899 by Friedrich Oskar Giesel. It is used as a neutron source and in radiation therapy for cancer treatment.

Overview

English Name:

Actinium

Latin Name:

Actinium

Year Discovered:

1899

Discovered By:

Friedrich Oskar Giesel

Group:

Period:

Electrons:

CAS Number:

7440-34-8

Cost Per 100 Grams:

$5000

Atomic Properties

Electronic Configuration:

[Rn] 6d¹ 7s²

Ion Charge:

Ionisation Energies:

499 kJ/mol

Atomic Radius (Empirical):

200 pm

Atomic Radius (Calculated):

248 pm

Covalent Radius:

200 pm

Van Der Waals Radius:

N/A

Ionisation Potential of An Atom:

5.17 eV

Electrons Per Layer:

2, 8, 18, 32, 18, 9, 2

Atomic Multiplicities Of The Gas:

Atomic Weight:

227

Oxidation States

Reactivity

Electron Affinity:

Not well defined

Valence:

Electronegativity:

1.1

Thermal Properties

Melting Point:

1050 °C

Boiling Point:

1500 °C

Critical Point:

Pressure: N/A

Temperature: N/A

Thermal Conductivity:

0.12 W/(m·K)

Heat Capacity:

Specific: 0.11 J/(g·K)

Molar: 26.5 J/(mol·K)

Thermal Coefficient:

0.0001

Enthalpy:

Fusion: 4.7 kJ/mol

Vaporisation: 130 kJ/mol

Atomization: 300 kJ/mol

Curie Temperature:

N/A

Neel Temperature:

N/A

Superconductivity Point:

N/A

Physical and Chemical Properties

State of matter (25° C/ 77°F):

Solid

Density:

Solid: 10.07 g/cm³

Molar Volume (Vmol):

22.5 cm³/mol

Speed of Sound (Vs):

Not applicable

Hardness:

N/A

Bulk Modulus (K):

Not available

Shear Modulus (G):

N/A

Young's Modulus (E):

N/A

Color:

Silvery-white

Brinell Hardness (MPa):

N/A

Liquid Density (Kg/m^3):

6.0 kg/m³

Hardness of Mohs:

N/A

Refractive Index:

N/A

Vickers Hardness (MPa):

N/A

Crystal Structure:

N/A

Electromagnetic Properties

Electrical Type:

Conductor

Resistivity:

10^-6 Ω·m

Magnetic Type:

Diamagnetic

Superconductivity:

Not applicable

Volume Magnetic Susceptibility:

-1.0 × 10^-9

Mass Magnetic Susceptibility:

-1.2 × 10^-9 m³/kg

Molar Mass Susceptibility:

-3.0 × 10^-8 m³/mol

Electrical Conductivity:

10^-6 S/m

Mass (γ_mass):

3.5 × 10^-25 kg

Mass (γ_mol):

3.5 × 10^-22 mol

Volume (γ_vol):

22.5 L

Grid Parameters

Crystal Structure:

N/A

Grid Parameters:

N/A

Attitude:

N/A

Debye Temperature:

N/A

Safety and Precautions

Signal Word:

Danger

Hazard Statements:

H300, H310, H330

Precautionary Statements:

P201, P202, P280, P308 + P313

RTECS Number:

Not available

Risk:

Flammability: Non-flammable
Health Risk: Highly toxic
Reactivity: Unstable
Specific Risk: Radioactive

Importance

Main sources:

Uranium and thorium ores

Main Usage:

Neutron source, radiation therapy

Nuclear Properties

Radioactive:

Yes

Isotopes:

Ac-227, Ac-228

Neutron Cross Sectional:

0.1 barns

Half Life (s):

21.77 years

Lifetime:

Stable

Prevalence

Universe:

0.0000000001%

Sun:

0.0000000001%

Oceans:

0.00000000001%

Humans:

0.000000000001%

Earth's Crust:

0.0000000001%

Meteorites:

0.0000000001%