Atomic / phase data
Reference atomic and phase values are source-reviewed.
Material structure
The ordinary elemental structure is measured/reviewed; the viewer is a teaching representation.
Element vs material uses
Uses distinguish elemental metal from compounds, alloys, doped hosts or isotope-specific systems.
Geography
Discovery/supply context is selective and does not fabricate deposits, facilities or inventories.
The lens describes evidence status, not confidence theatre. “Unknown” is kept unknown, and teaching schematics are not presented as direct measurements.
Terbium (Tb)
Terbium is element 65, a lanthanide whose Tb³⁺ emission and strong magnetic response connect the periodic table to green phosphors, solid-state devices and magnetostrictive materials.
Terbium atomic number, mass, electron configuration and key properties
Terbium: quick answers
How many protons, neutrons and electrons does terbium have?
Terbium’s atomic number is 65, so every terbium atom has 65 protons, and a neutral atom also has 65 electrons. Its most common natural isotope, terbium-159, has 94 neutrons (other isotopes have different neutron counts).
What is the symbol for terbium?
The chemical symbol for terbium is Tb.
Is terbium a solid, liquid or gas at room temperature?
Terbium is a solid at room temperature (about 25 °C).
What family (group) is terbium in?
Terbium is a lanthanide, in period 6 (the f-block row shown below the main table) of the periodic table.
What is the electron configuration of terbium?
The ground-state electron configuration of terbium is [Xe] 4f⁹ 6s².
From atomic number to chemistry
Read these as a chain of causes, not as isolated facts. Each step links to the concept hub if you want the underlying idea explained.
65 protons define terbium.
The ground-state configuration frames atomic and chemical behavior.
Periodic position organizes recurring chemistry and trends.
The teaching nucleus is one isotope, not the relative atomic mass.
Phase claims preserve source-reviewed evidence and material context.
Terbium in its period and family
Terbium follows gadolinium in the lanthanide series. Its 4f⁹6s² atom commonly gives Tb³⁺, while Tb⁴⁺ is also accessible in selected oxides.
Terbium Visual Lab
Explore Tb across the teaching nucleus, isolated-atom orbitals, evidence-aware material structure and temperature/evidence views, then connect those models to uses, isotopes, search-led questions and source-backed context.
Every mark points to one exact feature
The numbered markers explain the same information system used throughout Element Lookup. Unknown or predicted fields remain visibly labelled rather than being replaced with guesses.
Terbium in one minute
Atomic number 65 means every terbium nucleus has 65 protons.
Neutral Terbium has the ground-state configuration [Xe] 4f⁹ 6s².
The representative teaching isotope is ¹⁵⁹Tb.
The familiar green light associated with terbium comes from Tb³⁺ ions in host materials, not from metallic terbium glowing green.
The ordinary material reference is Hexagonal close-packed (HCP).
Shell rings organize electron counts. They are not electron trajectories or orbital shapes.
2 · 8 · 18 · 27 · 8 · 2 electrons
The displayed 4f_xyz orbital is one representative real f cubic harmonic. It is not a picture of the whole 4f subshell or the electronic bands in the bulk material.
Ordinary terbium metal is HCP. The viewer is a conventional teaching cell; terbium phosphors and magnetostrictive alloys have their own host/intermetallic structures.. The viewer is evidence-aware: measured structures are identified as such; unknown bulk structures stay unknown.
Teaching visualization; not a literal finite sample or thermal trajectory.What this model does—and does not—show
The displayed 4f_xyz orbital is one representative real f cubic harmonic. It is not a picture of the whole 4f subshell or the electronic bands in the bulk material.
Where do I meet terbium?
Clickable learning cards connect the element to materials, environment, technology, biology or research - depending on what the evidence actually supports.
Green phosphors
Tb³⁺ ions provide strong green emission in selected phosphor hosts used in lighting and displays.
4f⁹ → Tb³⁺ emission → green phosphors & magnetostriction
Terbium’s signature applications depend on Tb ions and intermetallic host materials. Elemental Tb metal is a separate HCP material.
4f⁹6s²
Open 4f shell with strong magnetic/optical character.
Terbium in periodic context
Compare nearby or family-related elements without treating a trend as a substitute for element-specific evidence.
| Atomic number | 64 |
|---|---|
| Series | lanthanide |
| Atomic number | 65 |
|---|---|
| Series | lanthanide |
| Atomic number | 66 |
|---|---|
| Series | lanthanide |
Terbium properties: atomic, physical, thermal and chemical
Categories follow the science of this element rather than a fixed decorative template. Each row carries condition/provenance context and an evidence label; unknown values stay unknown.
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| Atomic number | 65 | Source-reviewed; see Sources below | Evaluated |
| Relative atomic mass | 158.925 | Source-reviewed; see Sources below | Evaluated |
| Ground-state electron configuration | [Xe] 4f⁹ 6s² | Source-reviewed; see Sources below | Evaluated |
| Group / period / block | Group Lanthanide · Period 6 · f-block | Periodic-table placement | Evaluated |
| Electronegativity | 1.20 | Source-reviewed; see Sources below | Evaluated |
| Reference isotope | ¹⁵⁹Tb | Source-reviewed; see Sources below | Evaluated |
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| State context | Soft silvery lanthanide metal | Source-reviewed; see Sources below | Evaluated |
| Density | 8.23 g/cm³ | Source-reviewed; see Sources below | Evaluated |
| Material / molecular structure | Hexagonal close-packed (HCP) | Ordinary terbium metal is HCP. The viewer is a conventional teaching cell; terbium phosphors and magnetostrictive alloys have their own host/intermetallic structures. | Measured |
| Classification | Lanthanide | Periodic-table / chemistry classification | Evaluated |
| Structure-model scope | Ordinary terbium metal is HCP. The viewer is a conventional teaching cell; terbium phosphors and magnetostrictive alloys have their own host/intermetallic structures. | Teaching visualization; exact crystallographic coordinates are not implied unless stated. | Reviewed |
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| Melting / transition reference | 1632 K | Source-reviewed; see Sources below | Evaluated |
| Boiling / gas reference | 3503 K | Source-reviewed; see Sources below | Evaluated |
| Phase-path context | At approximately standard pressure, terbium is treated as a solid below 1632 K, liquid between melting and approximately 3503 K, and gas above the boiling reference. The ordinary crystal label applies to the stated material reference; unmodeled solid allotropy is not fabricated. | Shared phase registry drives the slider, regions and markers. | Evaluated |
| Condition warning | Temperature and pressure define phase behavior; purity/allotropy may matter. | Teaching condition statement | Reviewed |
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| Common oxidation states | +3, +4 | Source-reviewed; see Sources below | Evaluated |
| Ion / common ion context | Tb³⁺ | Source-reviewed; see Sources below | Evaluated |
| Periodic chemistry context | Terbium follows gadolinium in the lanthanide series. Its 4f⁹6s² atom commonly gives Tb³⁺, while Tb⁴⁺ is also accessible in selected oxides. | Element-specific interpretation | Reviewed |
| Chemistry caution | Elemental form, ions and compounds are distinct chemical objects. | Interpretive teaching rule | Reviewed |
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| ¹⁵⁹Tb | Natural isotope | Essentially all natural terbium is ¹⁵⁹Tb. | Evaluated |
| Radioisotopes | Artificial isotopes | Used primarily in research and isotope-specific applications. | Evaluated |
| Natural terbium | Single-isotope natural element | Relative atomic mass is therefore close to the ¹⁵⁹Tb isotope mass. | Evaluated |
| Teaching nucleus | ¹⁵⁹Tb · 65 protons + 94 neutrons | Reference isotope used in the nucleus model | Reviewed |
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| Page evidence note | Atomic identity and reference values are source-reviewed. Material viewers are teaching representations, not crystallographic refinements. Search demand shapes headings and FAQs but never overrides measured/evaluated evidence or element-versus-compound distinctions. | Evidence summary for this guide | Reviewed |
| Structure evidence | Ordinary terbium metal is HCP. The viewer is a conventional teaching cell; terbium phosphors and magnetostrictive alloys have their own host/intermetallic structures. | Measured structure, labelled schematic, prediction or explicit unknown as applicable. | Reviewed |
| Map evidence rule | Real pins are reviewed examples; conceptual layers are used when pins would mislead. | Geography Explorer 2.0 | Reviewed |
| Source set | 3 primary/reference links listed below | Open the Sources section for the actual references. | Reviewed |
Is Terbium a solid, liquid or gas? State at temperature
At approximately standard pressure, terbium is treated as a solid below 1632 K, liquid between melting and approximately 3503 K, and gas above the boiling reference. The ordinary crystal label applies to the stated material reference; unmodeled solid allotropy is not fabricated.
Where on Earth is Terbium found or produced?
Who discovered Terbium, and when?
Carl Gustaf Mosander separated terbium-containing oxide while studying yttria-derived rare-earth mixtures.
Early erbium/terbium names and fractions were historically confused as rare-earth chemistry developed.
Phosphor and magnetic applications grew with high-purity rare-earth separation.
Tb is a high-value specialty element in phosphors and magnetostrictive materials.
From source material to Terbium applications: high-level material path
Terbium is obtained from mineral or metallurgical feedstocks in which it is chemically associated with other elements rather than mined as abundant native metal.
Industrial separation and refining produce element-specific compounds or metal feedstock; this guide does not provide operational extraction recipes.
The refined material is converted into the particular alloy, compound, doped host or component required by the application.
Recycling and recovery depend on the host product, concentration and economics; application materials must not be confused with pure element.
What is terbium used for?
Green phosphors
Tb³⁺ is an important green-emitting activator in selected phosphor hosts.
Magnetostrictive alloys
Terbium contributes to large magnetostriction in Tb-Dy-Fe materials.
Optical materials
Tb-doped crystals and salts are used in specialized optical systems.
X-ray/lighting phosphors
Terbium-containing phosphors have roles in efficient luminescent materials.
Terbium isotopes and natural abundance
¹⁵⁹Tb
Natural isotopeEssentially all natural terbium is ¹⁵⁹Tb.
Radioisotopes
Artificial isotopesUsed primarily in research and isotope-specific applications.
Natural terbium
Single-isotope natural elementRelative atomic mass is therefore close to the ¹⁵⁹Tb isotope mass.
Five-question Terbium check
What is Terbium’s atomic number?
Which classification best fits Terbium?
What is the representative teaching isotope?
Which statement respects the material evidence?
Which rule should guide real-world uses?
Terbium questions students commonly ask
Each answer starts with the direct fact, then explains the chemistry, evidence or material context so the result is understandable rather than merely memorized.
What is terbium?
Short answer: Terbium is chemical element 65, symbol Tb, a soft silvery lanthanide metal.
Atomic number 65 means every terbium nucleus contains 65 protons. In the periodic table, Terbium is classified here as a lanthanide in Period 6 and Group Lanthanide. Terbium follows gadolinium in the lanthanide series. Its 4f⁹6s² atom commonly gives Tb³⁺, while Tb⁴⁺ is also accessible in selected oxides.
Key point: Tb is element 65; its periodic position and electron structure explain the rest of the page.
What is terbium used for?
Short answer: It is used in green phosphors, magnetostrictive alloys, solid-state devices and specialized optical materials.
Green phosphors: Tb³⁺ is an important green-emitting activator in selected phosphor hosts. Magnetostrictive alloys: Terbium contributes to large magnetostriction in Tb-Dy-Fe materials. The familiar green light associated with terbium comes from Tb³⁺ ions in host materials, not from metallic terbium glowing green. Terbium metal, phosphors and Tb-Dy-Fe magnetostrictive alloys must be kept separate.
Key point: Always distinguish the pure element from the compound, alloy, isotope or device material that actually performs the application.
Where is terbium found?
Short answer: It occurs in rare-earth minerals such as monazite, bastnäsite and euxenite and is separated from other lanthanides.
Terbium is obtained from mineral or metallurgical feedstocks in which it is chemically associated with other elements rather than mined as abundant native metal. 1843 Carl Gustaf Mosander separated terbium-containing oxide while studying yttria-derived rare-earth mixtures.
Key point: Natural occurrence, resources, production and recycling are different geography questions.
What is the chemical symbol for terbium?
Short answer: Tb. Its atomic number is 65.
The symbol Tb is the standardized chemical abbreviation for element 65. In a chemical formula, Tb identifies terbium atoms; a compound containing Tb is not automatically the same material as elemental terbium.
Key point: Tb always identifies element 65.
Who discovered terbium?
Short answer: Carl Gustaf Mosander identified terbium in 1843 during rare-earth separation work.
In 1843, Carl Gustaf Mosander separated terbium-containing oxide while studying yttria-derived rare-earth mixtures. In the 19th century, Early erbium/terbium names and fractions were historically confused as rare-earth chemistry developed.
Key point: Discovery credit follows the historical evidence and accepted attribution, not just the earliest claim.
Is terbium a metal?
Short answer: Yes. It is a lanthanide metal.
This guide classifies Terbium as a lanthanide. Its periodic position is Period 6, f-block, Group Lanthanide. Terbium follows gadolinium in the lanthanide series. Its 4f⁹6s² atom commonly gives Tb³⁺, while Tb⁴⁺ is also accessible in selected oxides.
Key point: Periodic-table classification describes recurring atomic/chemical behavior; it does not make every element in a column physically identical.
How many protons does terbium have?
Short answer: Every terbium nucleus has 65 protons.
Atomic number is defined by proton count, so 65 protons are what make an atom terbium. A neutral terbium atom also has 65 electrons, while isotopes can have different neutron counts without changing the element.
Key point: Atomic number = proton count.
Why is terbium used in green phosphors?
Short answer: Tb³⁺ ions can produce strong green emission when placed in suitable host materials; the host and oxidation state matter.
Terbium is element 65, a lanthanide whose Tb³⁺ emission and strong magnetic response connect the periodic table to green phosphors, solid-state devices and magnetostrictive materials. Green phosphors Tb³⁺ ions provide strong green emission in selected phosphor hosts used in lighting and displays.
Key point: The mechanism matters: connect the observed behavior to electron structure, bonding, phase or the specific material form rather than memorizing the result alone.
Scientific sources for Terbium
- Royal Society of Chemistry - Terbium
- NIST - Atomic Weights and Isotopic Compositions
- IUPAC - Periodic Table of Elements
Questions to ask next about Terbium
A good element lesson should lead to the next useful question, not end after a list of facts.
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