# Technetium
## ๐ง Technetium ยท 3D (three.js)
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*Technetium in the live three.js Elements explorer โ drag to orbit the atom, click any tile to compare, slide the temperature.* ยท [โถ open full](https://wikitube-elements.netlify.app/?el=Tc)
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**TL;DR.** Technetium (symbol **Tc**, atomic number **43**) is the lightest element with no stable isotopes and the first element humanity **made** before finding โ produced in 1937 from a discarded cyclotron part, named from the Greek *technetos*, "artificial." Its metastable isomer **Tc-99m** is the workhorse of nuclear medicine (~10 million diagnostic procedures a year), and its 1952 detection in red-giant starlight proved that stars forge heavy elements.
## Microsim To Do
*Claimable rows, house pattern. All real Wikipedia articles.*
- Technetium-99m generator โ the Mo-99/Tc-99m "cow": two coupled half-lives (67 h / 6 h), milk the column and watch secular-transient equilibrium rebuild
- Isotopes of technetium โ the odd-Z instability hole: chart of nuclides strip, EC left to Mo, ฮฒโป right to Ru
- Technetium star โ the Merrill argument: half-life vs. stellar age slider โ how much Tc survives if the star made it N years ago?
- S-process โ slow neutron capture random-walking up the valley of stability through Tc
- Mendeleev's predicted elements โ the periodic table with holes: predict eka-manganese's properties from its neighbors
- Type-II superconductor โ flux vortices enter above H_c1 (ties to the room's quantum vortex sim)
- Nuclear transmutation โ Tc-99 โ Tc-100 (16 s) โ Ru-100: waste to metal
- [[Beta_decay|Beta decay]] โ the clean NIST emitter: spectrum with no gamma line
## Links (Wikipedia order)
<!-- injected from _registry/childlinks/Technetium.json (2026-07-30T02:09:12Z) -->
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`Isopropyl_alcohol` ยท `Isostructural` ยท `Isotope` ยท `Isotopes_of_technetium` ยท `Jan-Olov_Liljenzin` ยท `Kelvin` ยท `Kidney` ยท [[Krypton]] ยท `Lanthanide` ยท `Lanthanide_contraction` ยท [[Lanthanum]] ยท `Latin` ยท `Lattice_constant` ยท `Lawrence_Berkeley_National_Laboratory` ยท [[Lawrencium]] ยท [[Lead]] ยท `List_of_chemical_element_name_etymologies` ยท `List_of_data_references_for_chemical_elements` ยท [[Lithium]] ยท `Liver` ยท [[Livermorium]] ยท `London_penetration_depth` ยท `Los_Alamos_National_Laboratory` ยท [[Lutetium]] ยท [[Magnesium]] ยท `Magnetic_field` ยท `Magnetic_susceptibility` ยท `Magnetism` ยท [[Manganese]] ยท `Manganese_heptoxide` ยท `Marie_Curie` ยท `Masataka_Ogawa` ยท `Mass_number` ยท `Mass_spectrometry` ยท `Masuria` ยท [[Meitnerium]] ยท `Melting_point` ยท `Mendeleev's_predicted_elements` ยท [[Mendelevium]] ยท [[Mercury_(element)]] ยท `Metal` ยท `Metastability` ยท `Minor_actinide` ยท `Molar_heat_capacity` ยท `Molybdate` ยท [[Molybdenum]] ยท [[Moscovium]] ยท 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[[Rubidium]] ยท [[Ruthenium]] ยท [[Rutherfordium]] ยท `S-process` ยท [[Samarium]] ยท `Sanskrit` ยท [[Scandium]] ยท [[Seaborgium]] ยท `Second_Battle_of_the_Masurian_Lakes` ยท `Selenide` ยท [[Selenium]] ยท `Sellafield` ยท [[Silicon]] ยท [[Silver]] ยท [[Sodium]] ยท `Solid` ยท `Specific_activity` ยท `Spectral_line` ยท `Spectrogram` ยท `Speed_of_sound` ยท `Spent_nuclear_fuel` ยท [[Spontaneous_fission]] ยท `Standard_deviation` ยท `Standard_temperature_and_pressure` ยท [[Steel]] ยท `Stellar_classification` ยท [[Strontium]] ยท `Strontium-90` ยท [[Sulfur]] ยท `Sulfuric_acid` ยท `Synthetic_element` ยท `Synthetic_radioisotope` ยท [[Tantalum]] ยท `Tarnish` ยท `Technetium(III)_bromide` ยท `Technetium(III)_chloride` ยท `Technetium(III)_iodide` ยท `Technetium(IV)_bromide` ยท `Technetium(IV)_chloride` ยท `Technetium(IV)_oxide` ยท `Technetium(IV)_sulfide` ยท `Technetium(V)_fluoride` ยท `Technetium(VII)_oxide` ยท `Technetium(VII)_sulfide` ยท `Technetium-99` ยท `Technetium-99m` ยท 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> **Official MAIN โ Chemical element, Z = 43.** Grounded in [Wikipedia: Technetium](https://en.wikipedia.org/wiki/Technetium) (fetched live 2026-07-08).
>
> โ **Not to be confused with Technitium โ the School** (Technitium.org, the oldest Space Mining school in Minnesota, which wears this element's name deliberately: one letter apart, same root โ *techne*, craft).
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## Key facts (infobox)
| | |
|---|---|
| Symbol ยท Z | Tc ยท 43 |
| Group ยท Period ยท Block | 7 ยท 5 ยท d-block |
| Neighbors | Mn (above) ยท Re (below) ยท Mo โ Tc โ Ru |
| Electron configuration | [Kr] 4dโต 5sยฒ |
| Appearance | shiny gray metal (platinum-like; usually gray powder) |
| Melting ยท Boiling | 2430 K (2157 ยฐC) ยท 4538 K (4265 ยฐC) |
| Density | ~11.4โ11.5 g/cmยณ (isotope-dependent) |
| Crystal structure | hexagonal close-packed (hcp) |
| Oxidation states | โ1 to +7; **+4 and +7** most common |
| Superconductivity | type-II below **7.46 K**; magnetic penetration depth second only to niobium |
| Natural occurrence | from decay only โ ~0.003 parts per **trillion** of crust |
| Predicted ยท Discovered | Mendeleev 1871 ("eka-manganese") ยท Perrier & Segrรจ 1937 |
| Most stable isotopes | Tc-97 (4.21 ยฑ 0.16 My) and Tc-98 (4.2 ยฑ 0.3 My) โ overlapping confidence intervals, so "most stable" is genuinely undecided; then Tc-99 (211,100 y) |
## History โ predicted, faked, made, then found in the stars
**The gap (1871).** Mendeleev's table had a hole between molybdenum (42) and ruthenium (44); he named the missing element *eka-manganese* and predicted its chemistry. The gap then collected six decades of false discoveries โ polinium (1828, actually iridium), pelopium, ilmenium, davyum, lucium, nipponium (1908, actually rhenium) โ and the disputed 1925 "masurium" claim of Noddack, Tacke, and Berg, later shown impossible (natural ores hold < 3 ร 10โปยนยน ฮผg/kg, undetectable by their methods).
**The making (1937).** Emilio Segrรจ persuaded Ernest Lawrence to mail him discarded, radioactive cyclotron parts from Berkeley โ a **molybdenum deflector foil**. In Palermo, Segrรจ and Carlo Perrier proved by comparative chemistry that the foil's activity was element 43. Palermo's officials lobbied for "panormium"; in 1947 it was named from *technetos* (ฯฮตฯฮฝฮทฯฯฯ), **"artificial" โ the first element to be artificially produced**. Segrรจ then isolated Tc-99m with Glenn Seaborg at Berkeley.
**The finding (1952).** Paul Merrill detected technetium's spectral lines (403.1, 423.8, 426.2, 429.7 nm) in S-type red giants. An element whose longest half-life is ~4 million years cannot be primordial in an old star โ so the stars must be **making it now**. Technetium in starlight became a proof of stellar nucleosynthesis and, later, evidence for the s-process. Such stars are called [technetium stars](https://en.wikipedia.org/wiki/Technetium_star).
**The trace (1962).** Tc-99 was finally found on Earth โ ~0.2 ng/kg in Belgian Congo pitchblende, as a spontaneous-fission product of U-238; the Oklo natural reactor shows fossil evidence of technetium since decayed to Ru-99.
## Properties
A silvery-gray transition metal between manganese and rhenium, chemically closer to rhenium (inertness, covalent bonding โ the lanthanide contraction at work). Nine oxidation states from โ1 to +7. Dissolves in aqua regia, nitric acid, and concentrated sulfuric acid โ but **not hydrochloric acid at any concentration**. Tarnishes slowly in moist air; the powder burns in oxygen. Below 7.46 K it is a **type-II superconductor** with a magnetic penetration depth greater than any element except niobium. The accessible workhorse compound is **sodium pertechnetate** Na[TcOโ]; the pertechnetate ion is a tetrahedral perchlorate-lookalike and only a weak oxidizer (unlike permanganate, its manganese cousin).
## Isotopes โ the odd-Z hole in the valley of stability
Every isotope is radioactive: Z = 43 is the lowest such atomic number (promethium, 61, is the only other all-radioactive element below bismuth's neighborhood โ and Tc and Pm are the only radioactive elements flanked by stable neighbors). Lighter isotopes decay by electron capture to molybdenum; Tc-98 and heavier by beta emission to ruthenium. **Tc-99** dominates in practice: fission of U-235 yields **6.1%** Tc-99 (27 mg per gram fissioned) โ an estimated **78 metric tons** accumulated from reactors 1983โ1994, dwarfing the natural trace. **Tc-99m** (6.01 h, 140 keV gamma) is the medical isomer, milked from Mo-99 (67 h) in the alumina-column "**technetium cow**" generator.
## Applications
- **Nuclear medicine** โ Tc-99m underlies **more than 50 radiopharmaceuticals**, imaging brain, heart, thyroid, lungs, liver, kidneys, bone, blood, and tumors; roughly ten million procedures a year. Supply is fragile: most Mo-99 came from a handful of 1960s-era reactors (Chalk River, Petten), and the 2008 MAPLE cancellations made the supply chain a standing policy problem; cyclotron routes via Mo-100(p,2n) are the modern workaround.
- **Metrology** โ Tc-99's clean, gamma-free beta emission and long half-life make it a **NIST standard beta source** for instrument calibration.
- **Corrosion inhibition** โ 55 ppm pertechnetate protects steel in water even at 250 ยฐC (one specimen sat 20 years uncorroded) โ but at 3 MBq/L the cure is radioactive, so it stays confined to sealed systems.
- **Catalysis** โ outperforms rhenium and palladium at dehydrogenation (e.g., isopropyl alcohol) โ same caveat.
- **Waste headache** โ anionic pertechnetate doesn't bind soil and escapes cation-focused cleanup (Cs, Sr), making Tc-99 the dominant radioactivity in spent fuel at the 10โดโ10โถ-year horizon; Sellafield discharged ~900 kg-equivalent to the Irish Sea 1995โ99 before regulation capped releases. CERN demonstrated **transmutation**: neutron-bombard Tc-99 โ Tc-100 (16 s) โ stable Ru-100.
**Safety.** Weak beta stopped by glassware; the real hazard is **inhaled dust** (lung dose). Fume hood suffices for most work. No biological role; low chemical toxicity; the body excretes pertechnetate quickly.
## Vocational-Technical Semiotics
The element of *made things* speaks the made signs: hazard pictograms ghs (radiological handling), isotope/decay-chain notation (the โนโนแตTc superscript grammar โ the "m" is itself a sign), orbital diagrams ([Kr] 4dโต 5sยฒ), crystallographic symbols (hcp, hP2), and the periodic table itself โ the sign system whose empty cell *predicted* this element sixty-six years before anyone made it. Mendeleev's gap is the canonical proof that a good notation generates knowledge.
## Sources
Grounded in [en.wikipedia.org/wiki/Technetium](https://en.wikipedia.org/wiki/Technetium), fetched live 2026-07-08 (all figures above โ half-lives per NUBASE2020 as cited there; fission yield 6.1%; 78 t 1983โ94; 7.46 K; 0.003 ppt; 55 ppm; 10M procedures โ taken from that revision). Deeper citations inherit from the article's own reference list (Schwochau 2000; Emsley 2001; Greenwood & Earnshaw 1997).
## Navigation
- Technitium โ the School (the disambiguation twin) ยท Space Mining In Minnesota CoE
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## Wikipedia : Wikitube
**Strict pair:** [Wikipedia](https://en.wikipedia.org/wiki/Technetium) : [Wikitube](https://en.wikitube.io/wiki/Technetium)
## Previous hub tags
Tree parents: [[Helium]] ยท [[Hydrogen]] ยท [[Oxygen]].
Legacy hubs: none.
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*Sources: 1 legacy note. Minted wave 1, 2026-07-30 (v1.6 order).*