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.
Gallery
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Physical Propertiesmass · density · phase · crystal
Atomic Mass
97.9072Da
Density
11g/cm³
Phase (STP)
Solid
Melting Point
2430.2K
Boiling Point
4535.1K
Molar Heat
—
Crystal Structure
HEX
Lattice Constant
2.740Å
Atomic Radiiatomic · covalent · van der Waals
Atomic (Empirical)
135.00pm
Covalent
128.00pm
Van der Waals
216.00pm
Electronic Propertieselectronegativity · ionization · affinity
Electron Configuration
[Kr] 4d5 5s2
Electron Shells
2, 8, 18, 13, 2
Electronegativity
2.10Pauling
Electron Affinity
0.6kJ/mol
1st Ionization Energy
7.1kJ/mol
Oxidation States
-3, -1, 0, +1, +2, +3, +4, +5, +6, +7
Orbital DiagramAufbau · Hund's rule · Pauli exclusion
Full: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d5 5s2Short: [Kr] 4d5 5s2
Ionization Energies (43 known)
Emission Spectrumvisible range · characteristic spectral lines
Abundanceby mass
Biological Role
Radioactive; no biological role. Tc-99m is the most used medical radioisotope for imaging.
Discovery
Discovered By
Carlo Perrier, Émillo Segrè
Named By
—
Year
1937
Nuclear Data
Known Isotopes
40
Stable Isotopes
3
Stable Mass Numbers
83, 84, 85