Tellurium

Tellurium (Te)

Silvery metalloid element of group 16. Eight natural isotopes, nine radioactive isotopes. Used in semiconductors and to a degree in some steels. Chemistry is similar to Sulphur. Discovered in 1782 by Franz Miller.
Atomic Number52
Atomic Weight127.6
Mass Number130
Group16
Period5
Blockp
Protons52 p+
Neutrons78 n0
Electrons52 e-
Tellurium element 2.jpg Animated Bohr Model Enhanced Bohr Model Bohr Model Orbital Diagram

Properties

Atomic Radius
140 pm
Atomic Volume
Covalent Radius
136 pm
Metallic Radius
137 pm
Ionic Radius
221 pm
Crystal Radius
206.99999999999997 pm
Van der Waals radius
206 pm
Density
6.232 g/cm³
Boiling Point
1,263 K
Melting Point
722.7 K
Electrons per shell2, 8, 18, 18, 6
Electronegativity
2.1
Electrophilicity
2.1412109472193 eV/particle
Proton Affinity
Electron Affinity
1.970876 eV/particle
Ionization Potential
9.00966 eV/particle
Heat of Vaporization
49.8 kJ/mol
Heat of Fusion
17.91 kJ/mol
Heat of Formation
196.6 kJ/mol
Molar Heat Capacity
25.73 J/(mol K)
Specific Heat Capacity
0.202 J/(g⋅K)
Thermal Conductivity
14.3 W/(m K)
Gas Basicity
Dipole Polarizability
38 a₀
C6 Dispersion Coefficient
445 a₀
Oxidation States-2, 2, 4, 5, 6
Color
Silver
Crystal StructureSimple Trigonal (HEX)
Lattice Constant
4.45 Å
Bulk Modulus
Electrical Resistivity
Electron Configuration[Kr] 4d10 5s2 5p4
Magnetic Ordering
Magnetic Susceptibility
PhaseSolid
Poisson Ratio
Shear Modulus
Young's Modulus
Allotropes
Alternate Names
Adiabatic Index
Appearance
Electric Conductivity
Critical Pressure
Critical Temperature
Curie Point
Electrical
Hardness
Magnetic Susceptibility
Magnetic
Neel Point
Neutron Cross Section
Neutron Mass Absorption
Gas Phase
Quantum Numbers
Refractive Index
Space Group
Speed of Sound
Superconducting Point
Thermal Expansion
Valence Electrons
Classification
CategoryMetalloids, Metalloids
CAS GroupVIB
IUPAC GroupVIA
Glawe Number94
Mendeleev Number102
Pettifor Number92
Geochemical Classsemi-volatile
Goldschmidt Classchalcophile
Radioactivity
RadioactiveNo
Decay Mode
Half-Life
Lifetime
Abundance
Abundance in Earth's crust
0.001 mg/kg
Abundance in Oceans
Abundance in Human Body
Abundance in Meteor
Abundance in Sun
Abundance in Universe9×10-7%

Isotopes of Tellurium

Stable Isotopes
120Te 122Te 123Te 124Te 125Te 126Te 128Te 130Te
Unstable Isotopes
105Te 106Te 107Te 108Te 109Te 110Te 111Te 112Te 113Te 114Te 115Te 116Te 117Te 118Te 119Te 121Te 127Te 129Te 131Te 132Te 133Te 134Te 135Te 136Te 137Te 138Te 139Te 140Te 141Te 142Te

History

Tellurium was discovered in Transylvania in 1782 by Franz-Joseph Müller von Reichenstein in a mineral containing tellurium and gold. In 1789, another Hungarian scientist, Pál Kitaibel, also discovered the element independently in an ore from Deutsch-Pilsen which had been regarded as argentiferous molybdenite. In 1798, it was named by Martin Heinrich Klaproth who earlier isolated it from the mineral calaverite. From the Latin word tellus, earth

DiscoverersFranz Müller von Reichenstein
Discovery LocationRomania
Discovery Year1782
Name OriginLatin: tellus (earth).
Tellurium and tellurium compounds are considered to be mildly toxic
In air, tellurium burns with a greenish-blue flames, forming the dioxide

Uses

The primary use of tellurium is in alloys, foremost in steel and copper to improve machinability. Tellurium is used as a basic ingredient in blasting caps, and is added to cast iron for chill control. It is used in vulcanizing rubber and in catalysts for petroleum cracking. Tellurium is used as a coloring agent in ceramics. Used to improve the machining quality of copper and stainless steel products and to color glass and ceramics. Also in thermoelectric devices. Some is used in the rubber industry and it is a basic ingredient in manufacturing blasting caps.

Sources

Obtained as a by-product of copper and lead refining.