Skip to Main Content

About Terbium

Terbium Bohr

In 1787, army-lieutenant and chemist Carl Axel Arrhenius found a rock in a quarry near the Swedish village of Ytterby which he suspected contained the newly discovered element tungsten. Analysis by other chemists did not bear out his suspicions, but ultimately four new elements were identified from Arrhenius’s ytterbite. Carl Gustaf Mosander isolated three new oxides in 1843, one of which he named terbia, giving the corresponding element the name terbium.

A variety of terbium-doped compounds can act as phosphors for use in television screens, other displays, lighting, or sensors. Most notably, terbium green phosphors are used in trichromatic fluorescent lamps along with europium blue and red phosphors to produce white light with greater energy efficiency than incandescent lighting. In zirconia oxide ceramics, terbium can act both as a light-emitting dopant and a crystal stabilizer, producing a material with excellent structural and optical properties. Other terbium doped compounds have useful electrical properties that make them potentially useful in the semiconductor industry.

Terfenol-D is an alloy of terbium, iron, and dysprosium that is magnetostrictive: it contracts or expands when exposed to magnetic fields. This property allows direct conversion between electrical and mechanical power, and the alloy is used in sensors, actuators, and acoustic and ultrasonic transducers, and active noise and vibration cancelling devices. Terbium was also a component of gadolinium-terbium-iron thin films used in magneto-optical memory storage devices and specialized compact discs (CD-MO), but other forms of computer memory are currently preferred for most applications. Additionally, engineered terbium-binding peptides are being developed for use as sensitive optical biosensors for sensing enzymatic activity, and several radioactive terbium isotopes are being developed for medical applications as diagnostic tracers or cancer treatments.

Terbium is a rare earth element and can be found in any rare earth containing mineral, but as a heavy rare earth element (HREE) it is more common in HREE-enriched minerals such as xenotime and euxenite. Additionally, terbium is present in ion adsorption clays, which are a major source of HREEs due to their relative ease of processing, despite the low percentage quantities of rare earths they contain.

+ Open All
- Close All

Elemental Terbium Terbium is primarily used in phosphors, particularly in fluorescent lamps and as the high intensity green emitter used in projection televisions, such as the yttrium-aluminum-garnet (Tb:YAG) variety. Terbium alloys are also used in magneto-optic recording films, such as Tb-Fe-Co. Terbium is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity). Elemental or metallic forms include pellets, rod, wire and granules for evaporation source material purposes. High Purity (99.999%) Terbium (Tb) Sputtering TargetTerbium nanoparticles and nanopowders provide ultra-high surface area which nanotechnology High Purity (99.999%) Terbium Oxide (Tb4O7) Powderresearch and recent experiments demonstrate function to create new and unique properties and benefits. Terbium oxide is available in powder and dense pellet form for such uses as optical coating and thin film applications. Oxides tend to be insoluble. Fluorides are another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Terbium is also available in soluble forms including chlorides, nitrates and acetates. These compounds can be manufactured as solutions at specified stoichiometries.

Terbium Properties

Terbium Bohr ModelTerbium (Tb) atomic and molecular weight, atomic number and elemental symbolTerbium is a Block F, Group 3, Period 6 element. The number of electrons in each of Terbium's shells is 2, 8, 18, 27, 8, 2 and its electronic configuration is [Xe]4f9 6s2. The terbium atom has a radius of and its Van der Waals radius is In its elemental form, CAS 7440-27-9, terbium has a silvery-white appearance. Terbium was discovered and first isolated by Carl Gustaf Mosander in 1842. It is named after "Ytterby", the town in Sweden where it was discovered.

Symbol: Tb
Atomic Number: 65
Atomic Weight: 158.93
Element Category: Lanthanide
Group, Period, Block: n/a, 6, f
Color: silvery-gray/ silvery white
Other Names: Terbio, Térbio
Melting Point: 1356°C, 2472.8°F, 1629.15 K 
Boiling Point: 3230°C, 5846°F, 3503.15 K
Density: 8219 kg/m3
Liquid Density @ Melting Point: 7.65 g·cm3
Density @ 20°C: 8.27 g/cm3
Density of Solid: 8219 kg·m3
Specific Heat: 0.0437 Cal/g/K @ 25 °C
Superconductivity Temperature: N/A
Triple Point: N/A
Critical Point: N/A
Heat of Fusion (kJ·mol-1): 16.3
Heat of Vaporization (kJ·mol-1): 391
Heat of Atomization (kJ·mol-1): 390.62
Thermal Conductivity: 0.111 W/cm/K @ 298.2 K
Thermal Expansion: (r.t.) (poly) 10.3 µm/(m·K)
Electrical Resistivity: (r.t.) (poly) 1.150 nΩ·m
Tensile Strength: 60 MPa
Molar Heat Capacity: 28.91 J·mol-1·K-1
Young's Modulus: ( form) 55.7 GPa
Shear Modulus: ( form) 22.1 GPa
Bulk Modulus: ( form) 38.7 GPa
Poisson Ratio: ( form) 0.261
Mohs Hardness: N/A
Vickers Hardness: 863 MPa
Brinell Hardness: 677 MPa
Speed of Sound: (20 °C) 2620 m·s-1
Pauling Electronegativity: N/A
Sanderson Electronegativity: N/A
Allred Rochow Electronegativity: 1.1
Mulliken-Jaffe Electronegativity: N/A
Allen Electronegativity: N/A
Pauling Electropositivity: N/A
Reflectivity (%): N/A
Refractive Index: N/A
Electrons: 65
Protons: 65
Neutrons: 94
Electron Configuration: [Xe]4f9 6s2
Atomic Radius: 177 pm
Atomic Radius,
non-bonded (Å):
Covalent Radius: 194±5 pm
Covalent Radius (Å): 1.81
Van der Waals Radius: 221 pm
Oxidation States: 4, 3, 2, 1 (weakly basic oxide)
Phase: Solid
Crystal Structure: hexagonal close-packed
Magnetic Ordering: paramagnetic
Electron Affinity (kJ·mol-1) Unknown
1st Ionization Energy: 565.77 kJ·mol-1
2nd Ionization Energy: 1111.52 kJ·mol-1
3rd Ionization Energy: 2114.01 kJ·mol-1
CAS Number: 7440-27-9
EC Number: 231-137-6
MDL Number: MFCD00011256
Beilstein Number: N/A
SMILES Identifier: [Tb]
InChI Identifier: InChI=1S/Tb
PubChem CID: 23958
ChemSpider ID: 22397
Earth - Total: 54 ppb
Mercury - Total: 41 ppb
Venus - Total: 56 ppb 
Earth - Seawater (Oceans), ppb by weight: 0.00014
Earth - Seawater (Oceans), ppb by atoms: 0.000005
Earth -  Crust (Crustal Rocks), ppb by weight: 940
Earth -  Crust (Crustal Rocks), ppb by atoms: 120
Sun - Total, ppb by weight: 0.1
Sun - Total, ppb by atoms: 0.001
Stream, ppb by weight: 0.008
Stream, ppb by atoms: 0.0001
Meterorite (Carbonaceous), ppb by weight: 40
Meterorite (Carbonaceous), ppb by atoms: 5
Typical Human Body, ppb by weight: N/A
Typical Human Body, ppb by atom: N/A
Universe, ppb by weight: N/A
Universe, ppb by atom: N/A
Discovered By: Carl Gustaf Mosander
Discovery Date: 1842
First Isolation: N/A

Health, Safety & Transportation Information for Terbium

Terbium is considered to be somewhat toxic. Safety data for Terbium and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the Products tab. The below information applies to elemental (metallic) Terbium.

Safety Data
Material Safety Data Sheet MSDS
Signal Word Danger
Hazard Statements H228
Hazard Codes F
Risk Codes 11
Safety Precautions N/A
RTECS Number N/A
Transport Information N/A
WGK Germany 3
Globally Harmonized System of
Classification and Labelling (GHS)

Terbium Isotopes

Naturally occurring terbium (Tb) has one stable isotope: 159Tb

Nuclide Isotopic Mass Half-Life Mode of Decay Nuclear Spin Magnetic Moment Binding Energy (MeV) Natural Abundance
(% by atom)
135Tb 135 0.94(+33-22) ms Unknown (7/2-) N/A N/A -
136Tb 135.96138(64)# 0.2# s Unknown N/A N/A 1063.04 -
137Tb 136.95598(64)# 600# ms Unknown 11/2-# N/A 1080.43 -
138Tb 137.95316(43)# 800# ms [>200 ns] ß+ to 138Gd; p to 137Gd N/A N/A 1088.51 -
139Tb 138.94829(32)# 1.6(2) s ß+ to 139Gd; ß+ + p to 139Eu 11/2-# N/A 1105.9 -
140Tb 139.94581(86) 2.4(2) s ß+ to 140Gd 5 N/A 1113.98 -
141Tb 140.94145(11) 3.5(2) s ß+ to 141Gd (5/2-) N/A 1122.06 -
142Tb 141.93874(32)# 597(17) ms ß+ to 142Gd; ß+ + p to 141Eu 1+ N/A 1139.46 -
143Tb 142.93512(6) 12(1) s ß+ to 143Gd (11/2-) N/A 1147.54 -
144Tb 143.93305(3) ~1 s ß+ to 144Gd 1+ N/A 1155.61 -
145Tb 144.92927(6) 20# min ß+ to 145Gd (3/2+) N/A 1173.01 -
146Tb 145.92725(5) 8(4) s ß+ to 146Gd 1+ N/A 1181.09 -
147Tb 146.924045(13) 1.64(3) h ß+ to 147Gd 1/2+# N/A 1189.17 -
148Tb 147.924272(15) 60(1) min ß+ to 148Gd 2- N/A 1197.25 -
149Tb 148.923246(5) 4.118(25) h ß+ to 149Gd; a to 145Eu 1/2+ N/A 1205.32 -
150Tb 149.923660(8) 3.48(16) h ß+ to 150Gd; a to 146Eu (2-) N/A 1213.4 -
151Tb 150.923103(5) 17.609(1) h ß+ to 151Gd; a to 147Eu 1/2(+) N/A 1221.48 -
152Tb 151.92407(4) 17.5(1) h ß+ to 152Gd; a to 148Eu 2- N/A 1229.56 -
153Tb 152.923435(5) 2.34(1) d EC to 153Gd 5/2+ 3.5 1237.64 -
154Tb 153.92468(5) 21.5(4) h EC to 154Gd; ß- to 154Dy 0(+#) 0.9 1245.72 -
155Tb 154.923505(13) 5.32(6) d EC to 155Gd 3/2+ 2 1253.8 -
156Tb 155.924747(5) 5.35(10) d EC to 156Gd; ß- to 156Dy 3- 1.4 1261.87 -
157Tb 156.9240246(27) 71(7) y EC to 157Gd 3/2+ 2 1269.95 -
158Tb 157.9254131(28) 180(11) y EC to 158Gd; ß- to 158Dy 3- 1.76 1278.03 -
159Tb 158.9253468(27) STABLE - 3/2+ 2.014 1286.11 100
160Tb 159.9271676(27) 72.3(2) d ß- to 160Dy 3- 1.79 1294.19 -
161Tb 160.9275699(28) 6.906(19) d ß- to 161Dy 3/2+ 2.2 1302.27 -
162Tb 161.92949(4) 7.60(15) min ß- to 162Dy 1- N/A 1310.35 -
163Tb 162.930648(5) 19.5(3) min ß- to 163Dy 3/2+ N/A 1309.11 -
164Tb 163.93335(11) 3.0(1) min ß- to 164Dy (5+) N/A 1317.19 -
165Tb 164.93488(21)# 2.11(10) min ß- to 165Dy 3/2+# N/A 1325.27 -
166Tb 165.93799(11) 25.6(22) s ß- to 166Dy N/A N/A 1333.35 -
167Tb 166.94005(43)# 19.4(27) s ß- to 167Dy 3/2+# N/A 1332.11 -
168Tb 167.94364(54)# 8.2(13) s ß- to 168Dy 4-# N/A 1340.19 -
169Tb 168.94622(64)# 2# s ß- to 169Dy 3/2+# N/A 1348.27 -
170Tb 169.95025(75)# 3# s ß- to 170Dy N/A N/A 1347.03 -
171Tb 170.95330(86)# 500# ms ß- to 171Dy 3/2+# N/A 1355.11 -