Neptunium

Neptunium is a chemical element with the symbol Np and atomic number 93. It is a silvery metal that is radioactive and is the first transuranium element. Neptunium is used in some types of nuclear reactors and as a source of neutrons in scientific research.

Overview

English Name:

Neptunium

Latin Name:

Neptunium

Year Discovered:

1940

Discovered By:

Edwin McMillan, Philip H. Abelson

Group:

Actinides

Period:

Electrons:

CAS Number:

7439-90-9

Cost Per 100 Grams:

$300

Atomic Properties

Electronic Configuration:

[Rn] 5f⁴ 6d¹ 7s²

Ion Charge:

+3, +4, +5

Ionisation Energies:

634 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:

6.65 eV

Electrons Per Layer:

2, 8, 18, 32, 21, 9, 2

Atomic Multiplicities Of The Gas:

Atomic Weight:

237.048

Oxidation States

Reactivity

Electron Affinity:

Not well defined

Valence:

3, 4, 5

Electronegativity:

1.36

Thermal Properties

Melting Point:

913 °C

Boiling Point:

4131 °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: 27.0 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: 20.25 g/cm³

Molar Volume (Vmol):

11.7 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

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 (γ_mass):

3.8 × 10^-25 kg

Mass (γ_mol):

3.8 × 10^-22 mol

Volume (γ_vol):

11.7 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%