Protactinium

Protactinium is a chemical element with the symbol Pa and atomic number 91. It is a dense, silvery-gray metal that is radioactive and occurs in trace amounts in uranium ores. Protactinium is used in nuclear reactors and research, particularly in the study of nuclear fission.

Overview

English Name:

Protactinium

Latin Name:

Protactinium

Year Discovered:

1913

Discovered By:

Otto Hahn, Lise Meitner

Group:

3

Period:

7

Electrons:

91

CAS Number:

7440-13-3

Cost Per 100 Grams:

$1000

Atomic Properties

Electronic Configuration:

[Rn] 5f² 6d¹ 7s²

Ion Charge:

+4

Ionisation Energies:

568 kJ/mol

Atomic Radius (Empirical):

200 pm

Atomic Radius (Calculated):

238 pm

Covalent Radius:

200 pm

Van Der Waals Radius:

N/A

Ionisation Potential of An Atom:

5.89 eV

Electrons Per Layer:

2, 8, 18, 32, 20, 9, 2

Atomic Multiplicities Of The Gas:

1

Atomic Weight:

231.04

Oxidation States

+4

Reactivity

Electron Affinity:

Not well defined

Valence:

4

Electronegativity:

1.5

Thermal Properties

Melting Point:

1,200 °C

Boiling Point:

4,000 °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: 24.3 J/(mol·K)

Thermal Coefficient:

0.0001

Enthalpy:

Fusion: 7.6 kJ/mol

Vaporisation: 200 kJ/mol

Atomization: 400 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: 15.37 g/cm³

Molar Volume (Vmol):

15.1 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-gray

Brinell Hardness (MPa):

N/A

Liquid Density (Kg/m^3):

12.0 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^-7 Ω·m

Magnetic Type:

Paramagnetic

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 (γmass):

3.8 × 10-25 kg

Mass (γmol):

3.8 × 10-22 mol

Volume (γvol):

15.1 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 ores

Main Usage:

Nuclear reactors, research

Nuclear Properties

Radioactive:

Yes

Isotopes:

Pa-231, Pa-233

Neutron Cross Sectional:

0.1 barns

Half Life (s):

32,760 years

Lifetime:

Stable

Prevalence

Universe:

0.0000000001%

Sun:

0.0000000001%

Oceans:

0.00000000001%

Humans:

0.000000000001%

Earth's Crust:

0.0000000001%

Meteorites:

0.0000000001%