Tellurium
Definition and meaning of Tellurium in chemistry.
Tellurium is a brittle, mildly toxic, rare silver-white metalloid with the symbol Te and atomic number 52. It is chemically related to selenium and sulfur, sharing many of their chalcogen group properties but exhibiting significantly greater metallic character.
In more detail
Positioned in group 16 of the periodic table, tellurium exhibits properties intermediate between metals and nonmetals, classifying it as a classic metalloid. It is relatively rare in the Earth's crust, comparable to the abundance of platinum, and is often found uncombined in nature or in compounds with gold and other metals as tellurides, such as calaverite (AuTe2). In its most common crystalline form, tellurium has a silvery-white luster and acts as a semiconductor, meaning its electrical conductivity is highly sensitive to light exposure and increases with temperature. When heated, tellurium burns in air with a distinctive greenish-blue flame to form tellurium dioxide (TeO2) and reacts aggressively with halogens to form various halides like tellurium tetrachloride (TeCl4). The element is frequently used in metallurgy to drastically improve the machinability of copper and stainless steel without significantly reducing their electrical conductivity, and is also utilized as a vulcanizing agent in rubber production to increase heat resistance.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Te |
| Atomic number | 52 |
| Atomic mass | 127.60 u |
| Category | Metalloid |
| State at room temperature | Solid |
| Melting point | 449.51 °C |
| Boiling point | 988 °C |
| Year discovered | 1782 |
Tellurium is a critical component in cadmium telluride (CdTe) solar panels, which are highly efficient, cost-effective thin-film photovoltaic devices that dominate the commercial utility-scale solar market due to their excellent light absorption capabilities.
Frequently asked questions
Is tellurium toxic to humans and what are the symptoms?
Yes, tellurium and its compounds are mildly toxic. A primary symptom of exposure is tellurium breath, where the body metabolizes the element into dimethyl telluride, causing the breath and sweat to smell strongly of garlic for weeks.
How is tellurium extracted commercially?
Tellurium is primarily obtained as a byproduct of copper refining. During the electrolytic refinement process of blister copper, anode slimes accumulate at the bottom of the cell, which contain recoverable quantities of tellurium alongside noble metals.