Tellurium Te

Discovery

In 1782 Franz-Joseph Müller von Reichenstein, a mining inspector in the Habsburg Empire, examined gold ore from Transylvania, in present-day Romania. He concluded that it contained a mysterious metal that was neither antimony nor bismuth and called it metallum problematicum.

His discovery attracted little attention until 1798, when the German chemist Martin Heinrich Klaproth analysed a sample, confirmed that it was a new element, credited Müller and gave it a name.

Tellurium also left a mark on the history of the periodic table. Its atomic weight (about 127.6) is higher than that of iodine (about 126.9), yet Mendeleev placed tellurium before iodine because of their chemical properties. Henry Moseley's work on atomic numbers in 1913 showed that this order was correct.

Origin of the name

The name comes from the Latin tellus, "earth". Selenium, discovered later, was named after the Moon to pair with it. The symbol is Te.

Main uses

• Solar panels: cadmium telluride thin-film modules are used in large solar farms and now account for a large share of tellurium demand.
• Thermoelectrics: bismuth telluride forms Peltier modules that cool one side when current flows, used in small fridges, wine coolers and laser temperature control; run in reverse, they generate electricity from temperature differences.
• Optical discs: germanium–antimony–tellurium alloys switch between crystalline and amorphous states under a laser and formed the recording layer of rewritable DVDs and Blu-ray discs.
• Metallurgy: small additions make steel and copper easier to machine.
• Rubber: tellurium compounds help vulcanise rubber.

Isotopes

Natural tellurium has eight isotopes, with tellurium-130 the most abundant at about 34%. Tellurium-128 and tellurium-130 are radioactive and decay by double beta decay. The half-life of tellurium-128, about 2 × 10²⁴ years, is the longest ever measured for any nuclide. Irradiating tellurium-130 with neutrons in a reactor is one way to produce medical iodine-131.

In everyday life

Tellurium is recovered mainly from the anode slimes left over from electrolytic copper refining. Its concentration in the crust is comparable to that of platinum.

People exposed to tellurium or its compounds produce dimethyl telluride, which gives the breath and sweat a strong, persistent garlic odour. Ordinary people are unlikely to encounter it, but workplaces handling it need to control dust and fumes. Gold tellurides such as calaverite are important gold ores in some regions.