Name

Selenium

Atomic Number

34

Allotropes

Amorphous Red Selenium, Amorphous Black Selenium, Monoclinic Selenium, Hexagonal Selenium

Appearance

Black, red, gray allotrope

Refractive Index

1.000895

Phase At STP

Solid

Spectrum Image

Source

CAS Number

7782-49-2

CID Number

{CID6326970, CID6326970, CID139346}

DOT Number

2658

RTECS Number

RTECSVS7700000

Mendeleev Number

101

Pettifor Number

93

Space Group Number

14

Glawe Number

95

Atomic Mass

78.9718 Da

Uncertainty

0.008

X Position

16

Y Position

4

Period

4

Group

16

Block

p

Category

Reactive Nonmetal

Geochemical

Semi-Volatile

Goldschmidt

Chalcophilic

Seawater

2e-10 kg/L

Earth Crust

5e-8 g

Human Body

0.000005 %

Solar System

0.000063 mole ratio to silicon

Meteorites

0.0013 %

Jmol

Molcas Gv

CPK

Empirical

115

Calculated

103

Van Der Waals

190

Bonding

190

Batsanov

190

Rahm

224

Dreiding

403

Uff

420.5

Mm3

229

Alvarez

182

Bragg

117

Covalent (Single Bound)

116

Covalent (Triple Bound)

107

Covalent (Cordero)

120

Covalent (Pyykko)

116

Covalent (Pyykko Double)

107

Covalent (Pyykko Triple)

107

Mendeleev

117

C12

140

Melting/Freeze (USE)

494 °K

Melting/Freeze (WEL)

494 °K

Melting/Freeze (CRC)

493.5 °K

Melting/Freeze (LNG)

490 °K

Boiling/Density (USE)

958 °K

Boiling/Density (WEL)

958 °K

Boiling/Density (CRC)

958 °K

Boiling/Density (LNG)

958 °K

Boiling/Density (Zhang)

958 °K

Critical Temperature

1766 °K

Critical Pressure

27.2 MPa

STP

4.81 kg/cm³

Solid (WEL)

4819 kg/cm³

Solid (CRC)

4810 kg/cm³

Solid (LNG)

4810 kg/cm³

Liquid (CR2)

3990 kg/cm³

Molar Volume

16.42 cm³/mol

Atomic Volume

16.5 cm³

Heat Of Fusion USE

5.23 kJ/mol

Heat Of Fusion CRC

6.69 kJ/mol

Heat Of Fusion LNG

6.69 kJ/mol

Heat Of Fusion WEL

5.4 kJ/mol

Evaporation USE

59.7 kJ/mol

Evaporation CRC

95.48 kJ/mol

Evaporation LNG

95.48 kJ/mol

Evaporation WEL

26 kJ/mol

Evaporation Zhang

95.5 kJ/mol

Molar Heat

25.363 J/molK

Heat Capacity CRC

25.363 J/gK

Heat Capacity LNG

24.98 J/gK

Heat Capacity WEL

25.36 J/gK

Thermal Conductivity

0.52 W/m*K

Adiabatic Index

N/A

Extensional

3350 m/s

Order

Diamagnetic

Susceptibility

-4e-9 m3/kg

Shear Modulus

3.7 GPa

Bulk Modulus

8.3 GPa

Poisson Ratio

0.33 ν

Youngs Modulus

10 GPa

Mohs

2

Brinell

736

Observed/Predicted By

J. Berzelius ve G. Gahn

Observed/Discovery Year

1817

Discovery Location

Isolated Sample By

J. Berzelius ve G. Gahn

Isolated Sample Year

1817

Half Life

Stable

Lifetime

Stable

Neutron Mass Absorption

0.0056

Neutron Cross Section

11.7

Electron Affinity (eV)

2.02067

Electron Affinity (kJ/mol)

194.9587

Electron Affinity (pauling)

2.55

Electron Affinity (allen)

14.34

Electron Affinity (ghosh)

0.2240328

Accepted

28.9

Uncertainty

1

C6 GB

233

C6 Coefficient

210

Constant Internal Default Radius

4.36

Constant

905.4, 908.3, 1160.1

Strucutre

HEX

Angles

π/2, 1.58493, π/2

Oxidation States

−2,−1,1,2,3,4,5,6

Electron Configuration

1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p4

Quantum Number

a burden

Electron Configuration Semantic

[Ar] 3d10 4s2 4p4

Shells-0

2

Shells-1

8

Shells-2

18

Shells-3

6

Ionization Energies-0

941

Ionization Energies-1

2045

Ionization Energies-2

2973.7

Ionization Energies-3

4144

Ionization Energies-4

6590

Ionization Energies-5

7880

Ionization Energies-6

14990