What is Tellurium's atomic number?

Tellurium has atomic number 52, meaning it has 52 protons in its nucleus. Its chemical symbol is Te, from the Latin tellus, meaning Earth.

Is Tellurium a metal or nonmetal?

Tellurium is classified as a metalloid (semimetal). It has a metallic luster but is brittle and behaves as a semiconductor — its electrical conductivity increases with temperature and with doping, unlike true metals.

What is Tellurium used for today?

The largest application is cadmium telluride (CdTe) thin-film solar cells, which account for a significant fraction of the global photovoltaic market. Tellurium is also used in bismuth telluride thermoelectric modules, phase-change memory (PCM) alloys (Ge-Sb-Te), and as an additive in steel and copper alloys to improve machinability.

What is Tellurium's electron configuration?

Tellurium's electron configuration is [Kr] 4d10 5s2 5p4. The four 5p electrons give it oxidation states of -2, +2, +4, and +6, with -2 and +4 being the most common in compounds.

Tellurium and its compounds are toxic at elevated exposures. Even tiny amounts absorbed by the body produce a distinctive garlic-like breath odor (dimethyl telluride) that can persist for weeks. Chronic exposure may cause nausea, somnolence, and nervous system effects.

Who discovered Tellurium?

Tellurium was discovered in 1782 by Franz-Joseph Muller von Reichenstein, an Austrian mining engineer, in gold ore from Transylvania. It was named and characterized more thoroughly by Martin Heinrich Klaproth in 1798.

Tellurium Element Properties

Explore the complete physical and chemical properties of Tellurium (Te, element 52) — from its metalloid semiconductor behavior to its role in solar cells and thermoelectrics.

127.60

Tellurium

Metalloid · Period 5 · Group 16

Melting Point

449.51 °C

Boiling Point

988 °C

Density

6.24 g/cm³

Atomic Mass

127.60 u

Electron Shell Configuration

[Kr] 4d¹⁰ 5s² 5p⁴

Shells: 2, 8, 18, 18, 6

Filter Properties

Property	Value
Element Name	Tellurium
Symbol	Te
Atomic Number	52
Atomic Mass	127.60 u
Category	Metalloid
Group	16 (VIA / Chalcogens)
Period	5
Block	p-block
CAS Number	13494-80-9
Discovered	1782 by Franz-Joseph Muller von Reichenstein
Named By	Martin Heinrich Klaproth (1798)
Named After	Latin tellus, meaning Earth
Standard State	Solid at 25 °C
Appearance	Silvery-white, lustrous, brittle solid
Crystal Structure	Hexagonal

Property	Value
Electron Configuration	[Kr] 4d10 5s2 5p4
Electrons Per Shell	2, 8, 18, 18, 6
Number of Protons	52
Number of Neutrons (Te-128)	76
Number of Electrons	52
Valence Electrons	6
Oxidation States	-2, +2, +4, +6
Electronegativity (Pauling)	2.1
Electron Affinity	190.2 kJ/mol
First Ionization Energy	869.3 kJ/mol
Second Ionization Energy	1790 kJ/mol
Third Ionization Energy	2698 kJ/mol
Atomic Radius (calc.)	123 pm
Covalent Radius	138 pm
Van der Waals Radius	206 pm
Stable Isotopes	Te-128 (31.74%), Te-130 (34.08%), Te-126 (18.84%)

Property	Value
Melting Point	449.51 °C (841.12 °F / 722.66 K)
Boiling Point	988 °C (1810 °F / 1261 K)
Density (at 25 °C)	6.24 g/cm³
Density (liquid, at m.p.)	5.70 g/cm³
Heat of Fusion	17.49 kJ/mol
Heat of Vaporization	52.55 kJ/mol
Specific Heat Capacity	0.202 J/(g·K)
Thermal Conductivity	2.35 W/(m·K)
Electrical Resistivity	4.36×10⁻⁴ Ω·m (at 25 °C)
Mohs Hardness	2.25
Crystal Structure	Hexagonal (space group P3121)
Magnetic Ordering	Diamagnetic
Speed of Sound	2610 m/s (thin rod, at 20 °C)
Thermal Expansion	18.0 µm/(m·K) (at 25 °C)
Bulk Modulus	65 GPa
Shear Modulus	16 GPa

Property	Value
Reactivity	Low; stable in dry air at room temperature
Reaction with Air	Burns with a blue-green flame forming TeO2
Reaction with Water	Negligible at room temperature
Reaction with Acids	Dissolves in concentrated H2SO4 and HNO3
Reaction with Halogens	Reacts readily with F2, Cl2, Br2 forming TeX2/TeX4
Common Compounds	TeO2, H2Te, CdTe, Bi2Te3, GeTe, Na2TeO3
Solar Cell Use	CdTe thin-film photovoltaics (major PV technology)
Thermoelectric Use	Bi2Te3 and PbTe modules for solid-state cooling/power
Memory Alloy Use	Ge-Sb-Te (GST) phase-change memory (PCM/OTS)
Metallurgy Use	Added to steel and copper to improve machinability
Rubber Use	Tellurium dibromide as vulcanization accelerator
Oxidation State Range	-2, +2, +4, +6 (-2 and +4 most common)
Semiconductor Behavior	Intrinsic p-type semiconductor; conductivity rises with temp
Toxicity	Toxic; causes garlic-breath odor (dimethyl telluride) even at low doses
Natural Occurrence	Primarily in calaverite (AuTe2), sylvanite, and as native tellurium
Global Production	~500 tonnes/year; mostly as byproduct of copper refining

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Summary

Tellurium (Te) is element 52 on the periodic table, a metalloid (semimetal) in group 16 (the chalcogens), period 5. It was discovered in 1782 by Franz-Joseph Muller von Reichenstein in ore samples from Transylvania. Tellurium is a brittle, silvery-white solid with a hexagonal crystal structure. As a semiconductor with p-type or n-type behavior depending on doping, it is prized in cadmium telluride (CdTe) thin-film solar cells, thermoelectric devices, and phase-change memory alloys. This reference tool presents all key physical, atomic, and chemical properties of Tellurium in one organized view.

How it works

All Tellurium property data is embedded directly in the page — no server call is needed.
Use the section tabs (Overview, Atomic, Physical, Chemical) to navigate different property groups.
Click any property row to copy its value to your clipboard.
The electron configuration diagram shows the shell distribution visually.
Use the search box to filter properties by name or value.

Use cases

Quick reference for students studying periodic table chalcogens and metalloids.
Verify Tellurium specs during materials science or photovoltaics research.
Teaching aid for illustrating semiconductor metalloid properties.
Look up Tellurium data for CdTe solar cell or thermoelectric device design.
Cross-check Tellurium toxicology data for lab safety planning.
Support chemistry homework and exam preparation.
Reference oxidation states for analytical or inorganic chemistry problems.
Explore Tellurium isotope abundance data for nuclear or radiochemistry work.

Frequently Asked Questions

Last updated: 2026-09-30 · Reviewed by Nham Vu