Tellurium
Tellurium is a brittle, silvery-white metalloid, one of the rarest stable elements in the Earth's crust. It's chemically similar to selenium and sulfur, and it's best known today for its role in high-efficiency thin-film solar cells and for a strange side effect: even minute exposure can leave a person with a persistent garlic-like breath odor.
- Group · Period
- 16 · 5
- At room temp
- solid
- Melts at
- 722.66 K
- Density
- 6.232 g/cm³
- Discovered
- 1782
Uses
Tellurium’s leading modern application is in cadmium telluride thin-film solar cells, which convert sunlight into electricity using a layer far thinner than conventional silicon panels require, making them lighter and often cheaper to produce at scale. Small amounts of tellurium are also alloyed into steel and copper to make the metal easier to machine, improving how cleanly it cuts without significantly weakening it.
Tellurium compounds additionally see use as a vulcanizing agent that improves the durability of rubber, and in certain thermoelectric materials that can generate electricity directly from a temperature difference, a property used in specialized power generation and cooling devices.
History
Tellurium was first identified in 1782 by Franz-Joseph Müller von Reichenstein, an Austrian mining official working in Transylvania, who noticed unusual properties in a gold ore but wasn’t able to fully confirm it as a new element. Credit for isolating and definitively characterizing it went to German chemist Martin Heinrich Klaproth in 1798, who also gave it its name, from the Latin tellus, meaning “earth.” For a rare element, tellurium’s practical importance has grown considerably in recent decades, driven largely by demand for its use in thin-film solar technology.
Fun facts
- Tellurium is one of the rarest stable elements found in the Earth's crust, rarer than most so-called rare-earth elements.
- Even tiny amounts of tellurium exposure can cause 'tellurium breath,' a strong, persistent garlic-like odor that can last for weeks.
- Cadmium telluride is used to make thin-film solar panels, an alternative to conventional silicon-based cells.
Frequently asked questions
Why does tellurium cause bad breath?
The human body converts tiny amounts of absorbed tellurium into a volatile compound that's released through the lungs and skin, and that compound has an intensely garlic-like smell. Because the body clears it slowly, even a small exposure can leave someone with noticeable "tellurium breath" for days or weeks, which is one reason it's handled carefully in labs and industry.
Is tellurium actually rarer than the rare-earth elements?
Yes, by most estimates — tellurium is one of the least abundant stable elements in the Earth's crust, scarcer than gold in some comparisons and scarcer than most of the lanthanide "rare earths," despite that group's name. Its scarcity is one reason tellurium compounds tend to be used in fairly small, high-value applications rather than bulk materials.
What does tellurium have to do with solar panels?
Cadmium telluride is a compound that absorbs sunlight very efficiently in an extremely thin layer, which makes it well suited to thin-film solar panels that use far less material than traditional silicon cells. That efficiency has made cadmium telluride one of the leading alternative solar cell technologies used commercially today.
Compounds
3 notable compounds containing Te
- Bi2Te3semiconductor
Bismuth telluride
A gray, layered crystalline semiconductor whose electrons carry heat and charge in a way that makes it the most efficient known material for converting small temperature differences directly into electricity near room temperature.
Used for: Peltier coolers and thermoelectric power generators
- CdTesemiconductor
Cadmium telluride
A crystalline compound of cadmium and tellurium whose band gap closely matches the peak intensity of sunlight, making it efficient at converting light directly into electricity.
Used for: Thin-film solar panels and infrared detector windows
- Ag2Temineral
Silver telluride
A dark, metallic-looking compound of silver and tellurium that occurs naturally as the mineral hessite, often found alongside gold in low-temperature ore deposits.
Used for: Studied as a topological insulator and thermoelectric material
Isotopes
42 known isotopes
Swipe to see all columns →
| Isotope | Natural abundance | Half-life | Decay mode | Mass excess | Binding energy / nucleon | Decay width |
|---|---|---|---|---|---|---|
| Te-120 stable | 0.09% | Stable | — | -89,362.16 keV | 8,476.99 keV | — |
| Te-122 stable | 2.55% | Stable | — | -90,313.28 keV | 8,478.13 keV | — |
| Te-123 | 0.89% | 9.2E+16 Y | Electron capture (100%) | -89,170.98 keV | 8,465.54 keV | 1.57 × 10-40 eV |
| Te-124 stable | 4.74% | Stable | — | -90,524.14 keV | 8,473.27 keV | — |
| Te-125 stable | 7.07% | Stable | — | -89,021.79 keV | 8,458.04 keV | — |
| Te-126 stable | 18.84% | Stable | — | -90,064.17 keV | 8,463.24 keV | — |
| Te-128 | 31.74% | 7.7E+24 Y | Double beta-minus decay (100%) | -88,993.79 keV | 8,448.75 keV | 1.88 × 10-48 eV |
| Te-130 | 34.08% | 0.79E+21 Y | Double beta-minus decay (100%) | -87,352.96 keV | 8,430.33 keV | 1.83 × 10-44 eV |
Show all 42 isotopes
| Te-104 | — | 18 ns | Alpha decay (100%), Two-proton emission | -49,626.83 keV | 8,157.33 keV | 2.53 × 10-8 eV |
| Te-105 | — | 0.62 us | Alpha decay (100%) | -52,811.51 keV | 8,186.84 keV | 7.36 × 10-10 eV |
| Te-106 | — | 70 us | Alpha decay (100%) | -58,219.76 keV | 8,236.77 keV | 6.52 × 10-12 eV |
| Te-107 | — | 3.1 ms | Alpha decay (70%), Electron capture / beta-plus decay (30%) | -60,657 keV | 8,258 keV | 1.47 × 10-13 eV |
| Te-108 | — | 2.1 s | Electron capture / beta-plus decay (51%), Alpha decay (49%), Beta-plus, proton emission (2.4%) | -65,781.68 keV | 8,303.72 keV | 2.17 × 10-16 eV |
| Te-109 | — | 4.4 s | Electron capture / beta-plus decay (96.1%), Beta-plus, proton emission (9.4%), Alpha decay (3.9%) | -67,715.4 keV | 8,319.33 keV | 1.04 × 10-16 eV |
| Te-110 | — | 18.6 s | Electron capture / beta-plus decay (100%), Alpha decay (0.00067%) | -72,229.82 keV | 8,358.12 keV | 2.45 × 10-17 eV |
| Te-111 | — | 19.3 s | Electron capture / beta-plus decay (100%), Beta-plus, proton emission | -73,587.49 keV | 8,367.76 keV | 2.36 × 10-17 eV |
| Te-112 | — | 2.0 m | Electron capture / beta-plus decay (100%) | -77,567.52 keV | 8,400.65 keV | 3.80 × 10-18 eV |
| Te-113 | — | 1.7 m | Electron capture / beta-plus decay (100%) | -78,347.04 keV | 8,404.64 keV | 4.47 × 10-18 eV |
| Te-114 | — | 15.2 m | Electron capture / beta-plus decay (100%) | -81,889.68 keV | 8,432.79 keV | 5.00 × 10-19 eV |
| Te-115 | — | 5.8 m | Electron capture / beta-plus decay (100%) | -82,062.77 keV | 8,431.15 keV | 1.31 × 10-18 eV |
| Te-116 | — | 2.49 h | Electron capture / beta-plus decay (100%) | -85,263.79 keV | 8,455.64 keV | 5.09 × 10-20 eV |
| Te-117 | — | 62 m | Electron capture / beta-plus decay (100%), Beta-plus decay (25%) | -85,095.5 keV | 8,450.92 keV | 1.23 × 10-19 eV |
| Te-118 | — | 6.00 d | Electron capture (100%) | -87,690.76 keV | 8,469.7 keV | 8.80 × 10-22 eV |
| Te-119 | — | 16.05 h | Electron capture / beta-plus decay (100%), Beta-plus decay (2.06%) | -87,182.54 keV | 8,462.08 keV | 7.90 × 10-21 eV |
| Te-121 | — | 19.17 d | Electron capture / beta-plus decay (100%) | -88,543.11 keV | 8,466.86 keV | 2.75 × 10-22 eV |
| Te-127 | — | 9.35 h | Beta-minus decay (100%) | -88,280.5 keV | 8,446.11 keV | 1.36 × 10-20 eV |
| Te-129 | — | 69.6 m | Beta-minus decay (100%) | -87,004.88 keV | 8,430.41 keV | 1.09 × 10-19 eV |
| Te-131 | — | 25.0 m | Beta-minus decay (100%) | -85,211.02 keV | 8,411.23 keV | 3.04 × 10-19 eV |
| Te-132 | — | 3.204 d | Beta-minus decay (100%) | -85,188.2 keV | 8,408.49 keV | 1.65 × 10-21 eV |
| Te-133 | — | 12.5 m | Beta-minus decay (100%) | -82,937.13 keV | 8,389.03 keV | 6.08 × 10-19 eV |
| Te-134 | — | 41.8 m | Beta-minus decay (100%) | -82,533.75 keV | 8,383.64 keV | 1.82 × 10-19 eV |
| Te-135 | — | 19.0 s | Beta-minus decay (100%) | -77,728.79 keV | 8,345.74 keV | 2.40 × 10-17 eV |
| Te-136 | — | 17.63 s | Beta-minus decay (100%), Beta-minus, neutron emission (1.31%) | -74,425.28 keV | 8,319.43 keV | 2.59 × 10-17 eV |
| Te-137 | — | 2.49 s | Beta-minus decay (100%), Beta-minus, neutron emission (2.99%) | -69,303.76 keV | 8,280.24 keV | 1.83 × 10-16 eV |
| Te-138 | — | 1.4 s | Beta-minus decay (100%), Beta-minus, neutron emission (6.3%) | -65,696 keV | 8,252.58 keV | 3.26 × 10-16 eV |
| Te-139 | — | 1.6 s | Beta-minus decay (100%), Beta-minus, neutron emission | -60,205.08 keV | 8,211.77 keV | 2.85 × 10-16 eV |
| Te-140 | — | 348 ms | Beta-minus decay (100%), Beta-minus, neutron emission | -56,367.45 keV | 8,183.36 keV | 1.31 × 10-15 eV |
| Te-141 | — | 193 ms | Beta-minus decay (100%), Beta-minus, neutron emission | -50,670 keV | 8,142 keV | 2.36 × 10-15 eV |
| Te-142 | — | — | Unknown | -46,550 keV | 8,113 keV | — |
| Te-143 | — | 408 ns | Beta-minus decay, Beta-minus, neutron emission, B-2N | -40,530 keV | 8,070 keV | 1.12 × 10-9 eV |
| Te-144 | — | — | Beta-minus decay (100%), B-2N, Beta-minus, neutron emission | -36,220 keV | 8,040 keV | — |
| Te-145 | — | — | Beta-minus decay (100%), B-2N, Beta-minus, neutron emission | -30,010 keV | 7,998 keV | — |