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Technetium Quick Reference

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Notes

Symbol

Tc

Atomic Number

43

Oxidation States

 7

more common with disagreement

 6

less common with disagreement

 5

less common with disagreement

 4

more common

 3

less common

 2

less common

 1

less common

 0

less common

-1

less common

-3

less common

Pauling Electronegativity

1.9

Electron Configuration

Orbital Occupancy

[Kr] 4d5 5s2

[Kr] represents the closed-shell electron configuration of krypton

Orbital Filling Order

[Kr] 5s2 4d5

[Kr] represents the closed-shell electron configuration of krypton

Term Symbol

6S5/2

see expanded configuration ...

Ionization Energies

I   (1)

 7.28 eV

II  (2)

15.26 eV

III (3)

29.54 eV

Electron Affinity

0.55 ± 0.20 eV  

4400 ± 1600 cm-1

Density

liquid, 2430.15 K

10.615 g/ml 

solid, 25 °C

11.000 g/cm3

Molar Volume

solid, 298 K, 1 atm

8.63 cm3/mol

Melting Point

2430.15 K

Boiling Point

1 atm

4538.15 K

Thermal Conductivity

solid

400 K, polycrystalline

50.0 W/(m K)

300 K, polycrystalline

50.7 W/(m K)

298.2 K, polycrystalline

50.7 W/(m K)

273.2 K, polycrystalline

50.9 W/(m K)

extrapolated

see all 10 conductivities ...

Pyykkö Covalent Radius

single bond

128 pm

double bond

120 pm

triple bond

110 pm

Atomic Radius

135 pm

Enthalpy of Fusion

1 atm

23.81 kJ/mol

Enthalpy of Vaporization

1 atm

585.22 kJ/mol

Quantity

Technetium Atomic Structure

Notes

Ionization Energies

I   (1)

 7.28 eV

II  (2)

15.26 eV

III (3)

29.54 eV

Electron Affinity

0.55 ± 0.20 eV  

4400 ± 1600 cm-1

Electron Binding Energies

K    (1s)

21044 eV  

LI   (2s)

 3043 eV  

LII  (2p1/2)

 2793 eV  

LIII (2p3/2)

 2677 eV  

see all 12 energies ...

Electron Configuration

Orbital Occupancy

[Kr] 4d5 5s2

[Kr] represents the closed-shell electron configuration of krypton

Orbital Filling Order

[Kr] 5s2 4d5

[Kr] represents the closed-shell electron configuration of krypton

Term Symbol

6S5/2

see expanded configuration ...

Clementi-Raimondi Effective Nuclear Charge

1s

Orbital Exponent

42.1090

ζ

Principle Quantum Number

1

n

Effective Nuclear Charge

42.1090

Zeff = ζ × n

2s

Orbital Exponent

15.8141

ζ

Principle Quantum Number

2

n

Effective Nuclear Charge

31.6282

Zeff = ζ × n

see all 10 effective nuclear charges ...

Screening Percentage

87.5%

Fluorescence Yields

ωK

0.782

ωL1

0.011

ωL2

0.037

ωL3

0.040

Coster-Kronig Yields

F12

0.10 

F13

0.57 

F23

0.118

Quantity

Technetium Physical Properties

Notes

Density

liquid, 2430.15 K

10.615 g/ml 

solid, 25 °C

11.000 g/cm3

Molar Volume

solid, 298 K, 1 atm

8.63 cm3/mol

Physical Form

hexagonal crystals

Young's Modulus

407.00 GPa

Poisson's Ratio

0.260

Electrical Resistivity

solid, 295 K

14×10-8 Ohm m

Superconducting Transition Temperature

lower purity

7.77 ± 0.02 K

higher purity

7.73 ± 0.02 K

cylindrical single crystals

7.46 ± 0.04 K

prepared by electrodeposition and reduction

7.46 ± 0.05 K

Superconducting Critical Magnetic Field at Absolute Zero

1410×10-4 T

Isothermal Bulk Modulus

300 K

297 GPa

estimated

Isothermal Compressibility

300 K

0.0034 GPa-1

estimated

Quantity

Technetium Atomic Interaction

Notes

Oxidation States

 7

more common with disagreement

 6

less common with disagreement

 5

less common with disagreement

 4

more common

 3

less common

 2

less common

 1

less common

 0

less common

-1

less common

-3

less common

Pauling Electronegativity

1.9

Allred-Rochow Electronegativity

1.36

Configuration Energy

electron volt units

8.94 eV

Pauling units

1.51   

Ghosh-Gupta Electronegativity

3.2244 eV

Nagle Electronegativity

1.30

Cohesive Energy

per mole

661 kJ/mol    

per atom

  6.85 eV/atom

Quantity

Technetium Thermodynamics

Notes

Melting Point

2430.15 K

Boiling Point

1 atm

4538.15 K

Thermal Conductivity

solid

400 K, polycrystalline

50.0 W/(m K)

300 K, polycrystalline

50.7 W/(m K)

298.2 K, polycrystalline

50.7 W/(m K)

273.2 K, polycrystalline

50.9 W/(m K)

extrapolated

see all 10 conductivities ...

Critical Point

11500 K

Vapor Pressure

4621 °C

100 kPa

3961 °C

10 kPa

3453 °C

1 kPa

3051 °C

100 Pa

2725 °C

10 Pa

2454 °C

1 Pa

Enthalpy of Fusion

1 atm

23.81 kJ/mol

Enthalpy of Vaporization

1 atm

585.22 kJ/mol

Electronic Heat Capacity Coefficient

4.30 mJ/(mol K2)

Debye Temperature

Low Temperature Limit ( 0 K )

454 K

Room Temperature ( 298 K )

422 K

Quantity

Technetium Identification

Notes

CAS Number

7440-26-8

Quantity

Technetium Atomic Size

Notes

Atomic Radius

135 pm

Orbital Radius

139.1 pm

Pyykkö Covalent Radius

single bond

128 pm

double bond

120 pm

triple bond

110 pm

Cordero Covalent Radius

147 pm

Shannon-Prewitt Crystal Radius

ion charge: +4, coordination number: 6

78.5 pm

ion charge: +5, coordination number: 6

74 pm  

ion charge: +7

coordination number: 4

51 pm  

coordination number: 6

70 pm  

Shannon-Prewitt Effective Ionic Radius

ion charge: +4, coordination number: 6

64.5 pm

ion charge: +5, coordination number: 6

60 pm  

ion charge: +7

coordination number: 4

37 pm  

coordination number: 6

56 pm  

Batsanov Crystallographic Van Der Waals Radius

205 pm

Batsanov Equilibrium Van Der Waals Radius

237 pm

Slater Atomic-Ionic Radius

135 pm

Quantity

Technetium Crystal Structure

Notes

Nearest Neighbor Distance

300 K, 1 atm

271 pm

Atomic Concentration

300 K, 1 atm

7.04×1022 cm-3

Quantity

Technetium History

Notes

Discovery

date of discovery

1937

discoverer

Emilio Gino Segrè

birth

1905

death

1989

discoverer

Carlo Perrier

birth

1886

death

1948

location of discovery

Palermo, Silicy, Italy

Origin of Element Name

origin

tekhnetos

origin description

property—Greek for artificial

Origin of Element Symbol

symbol: Tc

origin

technetium

origin description

element name

Formerly Used or Proposed Element Names and Symbols

name

trinacrium

no matching symbol specified

name

moseleyum

matching symbol

Ms

name

masurium

matching symbol

Ma

name

moselium

no matching symbol specified

name

neomolybdenum

no matching symbol specified

name

nipponium

matching symbol

Np

name

lucium

no matching symbol specified

name

ekamanganese

matching symbol

Em

name

davyum

matching symbol

Da

name

pelopium

matching symbol

Pe

name

ilmenium

no matching symbol specified

name

polinium

no matching symbol specified

Quantity

Technetium Nomenclature

Notes

Element Names in Other Languages

French

technétium

German

Technetium

Italian

tecneto

Spanish

tecnecio

Portuguese

tecnécio

Anions or Anionic Substituent Groups

technetide

Cations or Cationic Substituent Groups

technetium

Ligands

technetido

Heteroatomic Anion

technetate

'a' Term—Substitutive Nomenclature

techneta

'y' Term—Chains and Rings Nomenclature

technety

References    (Click the button next to a value above to see complete citation information for that entry)

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