Tellurium (Te)


  • Symbol: Te
  • Atomic Number: 52
  • Atomic Weight: 127.60
  • Element Classification: Metalloid
  • Discovered By: Franz-Joseph Müller von Reichenstein
  • Discovery Date: 1782
  • Name Origin: From the Latin ‘tellus’, meaning earth
  • Density(g/cc): 6.232
  • Melting Point: 449.51°C
  • Boiling Point: 988°C
  • Appearance: Silvery-white, brittle, and mildly toxic metalloid
  • Atomic Radius(pm): 140


Tellurium was discovered in 1782 by the Austrian mineralogist Franz-Joseph Müller von Reichenstein, who was the chief inspector of mines in Transylvania. While analyzing gold ores from the mines in that region, he identified a new element that he initially mistook for antimony or bismuth. After further investigation, he concluded that the substance was neither and had discovered a new element. Martin Heinrich Klaproth, who isolated the element in 1798, named it “tellurium” after the Latin word for earth, ‘tellus’, in recognition of its terrestrial origin.

Relation to Other Elements

Tellurium is a metalloid, positioned in group 16 of the periodic table, sharing the group with oxygen, sulfur, selenium, and polonium. This group is characterized by its members’ ability to form various oxidation states, with tellurium commonly exhibiting the -2, +4, and +6 states. Tellurium’s properties are intermediate between those of metals and nonmetals, similar to selenium, but it is less abundant and has more pronounced metallic characteristics compared to sulfur and selenium.

Natural Occurrence

Tellurium is one of the rarest stable elements in the Earth’s crust. It is most often found in combination with other elements, such as in the minerals calaverite (gold telluride, AuTe₂) and sylvanite (silver gold telluride). It can also be found in copper, lead, and gold ores. The majority of tellurium production results from the refining of copper and lead ores, where it is recovered from the byproducts.


Tellurium has several specialized uses due to its unique properties:

  • Alloys and Metallurgy: Adding small amounts of tellurium improves the machinability of copper and stainless steel, making them easier to cut and shape.
  • Thermoelectric Devices: Tellurium is used in thermoelectric materials, such as bismuth telluride, which can convert temperature differences directly into electrical energy, useful in power generation and cooling applications.
  • Solar Cells: Cadmium telluride (CdTe) is used in thin-film solar cells for its efficient conversion of sunlight into electricity.
  • Rubber Production: Tellurium can be used as a vulcanizing agent and accelerator in the rubber manufacturing process, enhancing the rubber’s resistance to heat and abrasion.
  • Electronics: Tellurium is used in the production of rewritable optical discs (CDs and DVDs) and phase-change memory chips.

The discovery of tellurium expanded the understanding of metalloids and their applications in technology and industry. Despite its rarity, tellurium’s role in enhancing metallurgical processes, its use in renewable energy technologies, and its contribution to electronics demonstrate the importance of even the less common elements in modern technological advancements.


Antimony (Sb)

Iodine (I)