Periodic Table

Technetium

Transition Metal

Quick Facts about Technetium

Mo
  • solid- state of matter at room temperature
  • Radioactive- no stable isotopes exist
  • +7, +6, +4- common oxidation states in compounds
  • HEX- crystal structure, atomic arrangement in solid form
Ru

Technetium (Tc) is element 43 on the periodic table. Atomic mass of Tc: 98.0000 u. Tc is in period 5, group 7. Melting point of Tc: 2430.00 K.Density of Tc: 11.00 g/cm³.

Why Technetium Matters

Technetium in medicine and industry

In Your Home

  • If you've had a bone, heart, or brain scan, 99ᵐTc was likely injected into you

Industry Uses

Medical imaging99ᵐTc is the most used medical radioisotope—over 30 million diagnostic scans yearly worldwide
Corrosion preventionTrace amounts in closed-loop cooling systems (power plants, industrial) prevent steel corrosion
ResearchStudied for superconductor applications; technetium becomes superconducting at 7.5 K

In Your Body

✗ Not essential

99ᵐTc is used extensively in nuclear medicine. Can image bones, hearts, brains, and tumors. No natural biological role.

Safety: Short half-life (6 hours) limits radiation exposure

Discovery of Technetium

Discovered by Carlo Perrier, Émillo Segrè in Italy, 1937

Name origin: Greek: technêtos (artificial).

History & Events

1937
First artificially produced element
1937
Name means 'artificial' from Greek 'technetos'
1937
Discovered by Carlo Perrier and Emilio Segrè in 1937
1937
Fills the gap Mendeleev predicted

About Technetium

Radioactive metallic transition element. Can be detected in some stars and the fission products of uranium. First made by Perrier and Segre by bombarding molybdenum with deutrons, giving them Tc-97. Tc-99 is the most stable isotope with a half-life of 2.6*10^6 years. Sixteen isotopes are known. Organic technetium compounds are used in bone imaging. Chemical properties are intermediate between rhenium and manganese.

Atomic Properties of Tc

Atomic Number of Tc
43
Atomic Mass of Tc
98.0000 u
Electron Configuration
[Kr] 4d5 5s2
Electronegativity
1.90
Block
d-block
Group
7
Period
5

Physical Properties of Tc

Phase (STP)
solid
Melting Point of Tc
2430.00 K
Boiling Point of Tc
4538.00 K
Density of Tc
11.0000 g/cm3

Thermal Properties

Heat of Fusion
23.80 kJ/mol
Heat of Vaporization
585.00 kJ/mol
Thermal Conductivity
50.60 W/m·K

Atomic Radii

Calculated
135 pm
Covalent
128 pm
Van der Waals
216 pm
Metallic
127 pm

Common Misconceptions

Wrong:Technetium doesn't exist in nature.
Correct:Trace amounts occur naturally from spontaneous uranium fission—about 1 nanogram per kg of uranium ore.
Wrong:Radioactive isotopes are too dangerous for medicine.
Correct:99ᵐTc's 6-hour half-life means it decays before causing harm, while its gamma rays easily escape the body for imaging.
Wrong:Artificial elements have no practical use.
Correct:Technetium is the most important element in nuclear medicine—30+ million scans yearly depend on it.

Isotopes of Technetium

Technetium has 0 naturally occurring isotopes, plus 4 notable radioactive isotopes.

IsotopeAtomic Mass (u)AbundanceHalf-LifeDecay Mode
9743Tc (Tc-97)Technetium-97 isotope96.90636670%4.21 million yearsEC
9843Tc (Tc-98)Technetium-98 isotope97.90721240%4.2 million yearsβ⁻
9943Tc (Tc-99)Technetium-99 isotope98.90625080%211,100 yearsβ⁻
99m43Tc (Tc-99m)Technetium-99m isotope98.90625080%6.01 hoursIT, γ

Data source: NIH PubChem (aggregated from IUPAC, NIST)

Isotope Applications

Isotopes of Technetium have important real-world applications in science and industry.

Medical Applications

99ᵐTc is a metastable isomer of 99Tc with a 6-hour half-life. Used to label compounds for kidney, liver, bone, and heart imaging. 99ᵐTc radiopharmaceuticals target tumors for SPECT/CT imaging. 99ᵐTc-MDP (medronate) detects bone metastases from prostate, lung, and thyroid cancers.

Uses

Added to iron in quantities as low as 55 part-per-million transforms the iron into a corrosion-resistant alloy.

Sources

Made first by bombarding molybdenum with deuterons (heavy hydrogen) in a cyclotron.

Geochemistry

Goldschmidt
synthetic

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