Selenium

Overview

English Name:

Selenium

Latin Name:

Se

Year Discovered:

1817

Discovered By:

Jöns Jacob Berzelius

Group:

16

Period:

4

Electrons:

34

CAS Number:

7782-49-2

Cost Per 100 Grams:

$1

Atomic Properties

Electronic Configuration:

[Ar] 3d¹⁰ 4s² 4p⁴

Ion Charge:

-2

Ionisation Energies:

941 kJ/mol

Atomic Radius (Empirical):

120 pm

Atomic Radius (Calculated):

198 pm

Covalent Radius:

116 pm

Van Der Waals Radius:

200 pm

Ionisation Potential of An Atom:

20.98 eV

Electrons Per Layer:

2, 8, 18, 6

Atomic Multiplicities Of The Gas:

1

Atomic Weight:

78.96

Reactivity

Electron Affinity:

194 kJ/mol

Valence:

2

Electronegativity:

2.55

Thermal Properties

Melting Point:

221°C

Boiling Point:

685°C

Critical Point:

Pressure: 5.1 MPa

Temperature: 685°C

Thermal Conductivity:

0.204 W/(m·K)

Heat Capacity:

Specific: 0.33 J/(g·K)

Molar: 25.8 J/(mol·K)

Thermal Coefficient:

0.0001

Enthalpy:

Fusion: 0.31 kJ/mol

Vaporisation: 4.7 kJ/mol

Atomization: 200 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: 4.81 g/cm³

Molar Volume (Vmol):

16.63 cm³/mol

Speed of Sound (Vs):

3000 m/s

Hardness:

N/A

Bulk Modulus (K):

5.5 GPa

Shear Modulus (G):

N/A

Young's Modulus (E):

N/A

Color:

Gray

Brinell Hardness (MPa):

N/A

Liquid Density (Kg/m^3):

2.55 kg/m³

Hardness of Mohs:

2.5

Refractive Index:

1.0002

Vickers Hardness (MPa):

N/A

Crystal Structure:

Hexagonal

Electromagnetic Properties

Electrical Type:

Semiconductor

Resistivity:

10^5 Ω·m

Magnetic Type:

Diamagnetic

Superconductivity:

Not applicable

Volume Magnetic Susceptibility:

-1.8 × 10^-5

Mass Magnetic Susceptibility:

-2.0 × 10^-5 m³/kg

Molar Mass Susceptibility:

-4.0 × 10^-4 m³/mol

Electrical Conductivity:

10^-4 S/m

Mass (γ_mass):

4.8 × 10^-26 kg

Mass (γ_mol):

4.8 × 10^-23 mol

Volume (γ_vol):

16.63 L

Grid Parameters

Crystal Structure:

Hexagonal

Grid Parameters:

a = 4.45 Å, c = 5.50 Å

Attitude:

N/A

Debye Temperature:

N/A

Safety and Precautions

Signal Word:

Warning

Hazard Statements:

H302

Precautionary Statements:

P261, P264, P270

RTECS Number:

Not available

Risk:

Flammability: Non-flammable
Health Risk: Toxic
Reactivity: Stable
Specific Risk: None

Importance

Main sources:

Industrial processes

Main Usage:

Glassmaking, pigments, electronics

Nuclear Properties

Radioactive:

No

Isotopes:

Se-74, Se-76, Se-77

Neutron Cross Sectional:

0.045 barns

Half Life (s):

None

Lifetime:

Stable

Prevalence

Universe:

0.00089%

Sun:

0.00089%

Oceans:

0.000006%

Humans:

0.00004%

Earth's Crust:

0.02%

Meteorites:

0.0005%