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About Technetium

Technetium Bohr

By the early twentieth century, what we know as the modern periodic table had largely taken shape. For the most part, what chemical discoveries remained would require the use of nuclear reactors rather than the traditional chemist’s patient examination and chemical analysis of unusual ores. There were, however, a few holes remained in the table, including the spot reserved for element 43, which by this time had acquired a long and troubled history. As early as 1828, various investigators claimed to have isolated a new element which would fill this hole, but for the next century, every scientist who put forth this claim was eventually proven false.

Eventually theoretical work provided an explanation for these many failures, establishing that element 43 would be unstable, and therefore impossible to isolate in appreciable quantities from natural sources. This led to attempts to produce element 43 in a laboratory, including those of the Italian chemists Carlo Perrier and Emilo Segre, which proved successful in December 1936. Thus the new element technetium became the first element to be artificially produced, and to this day remains the only element to ever be discovered in Italy.

Though technetium is known to exhibit some useful chemical properties, including the ability to protect steel from corrosion in aqueous solutions, its radioactivity precludes most avenues for exploiting these properties. The primary applications for the element are related to its radioactivity. The short-lived gamma-emitter technectium-99m (a medical isomer of technetium-99) is useful medically, as it can be bound to a number of compounds used by the body. It is routinely used in medical imaging of a variety of organ systems. Technetium-99, on the other hand, decays slowly by emitting only beta particles, and is in fact used as a standard beta emitter for equipment calibration. This same isotope also has potential for use in specialized applications such as nuclear batteries.

Tc-99 is routinely produced as a component of radioactive waste from nuclear power plants, from which it can be isolated. Tc-99m has a very short half-life, and must be produced from the radioactive decay of molybdenum-99, which itself is produced by irradiating uranium in dedicated reactors.

Technetium Properties

Technetium Bohr ModelTechnetium is a Block D, Group 7, Period 5 element. The number of electrons in each of Technetium's shells is 2, 8, 18, 13, 2 and its electron configuration is [Kr] 4d5 5s2. The technetium atom has a radius of 135.2.pm and its Van der Waals radius is 200.pm. In its elemental form, CAS 7440-26-8, technetium has shiny gray appearance. Technetium is produced as a byproduct of the nuclear industry from spent nuclear fuel rods and was the first element to be made artificially. This is indicated by its name which originates from the Greek word "technetos" meaning artificial. Nearly all technetium is synthetically produced; however, it is found in nature in minute amounts as a result of naturally occurring spontaneous fission or neutron capture by molybdenum. Technetium was discovered by Carlo Perrier and Emilio Segre in 1937. Technetium is used in nuclear medicine for a wide variety of diagnostic tests.

Technetium information, including technical data, properties, and other useful facts are specified below. Scientific facts such as the atomic structure, ionization energy, abundance on Earth, conductivity, and thermal properties are included.

Symbol: Tc
Atomic Number: 43
Atomic Weight: 98
Element Category: transition metal
Group, Period, Block: 7, 5, d
Color: silver-gray/silvery gray metallic
Other Names: N/A
Melting Point: 2157 °C, 3914.6 °F, 2430.15 K
Boiling Point: 4265 °C, 7709 °F, 4538.15  K
Density: 11 g·cm3
Liquid Density @ Melting Point: N/A
Density @ 20°C: 11.5 g/cm3
Density of Solid: 11500 kg·m3
Specific Heat: N/A
Superconductivity Temperature: 7.8 [or -265.3 °C (-445.5 °F)] K
Triple Point: N/A
Critical Point: N/A
Heat of Fusion (kJ·mol-1): 11.3
Heat of Vaporization (kJ·mol-1): 357
Heat of Atomization (kJ·mol-1): 356.69
Thermal Conductivity: 50.6 W·m-1·K-1
Thermal Expansion: N/A
Electrical Resistivity: N/A
Tensile Strength: N/A
Molar Heat Capacity: 24.27 J·mol-1·K-1
Young's Modulus: N/A
Shear Modulus: N/A
Bulk Modulus: N/A
Poisson Ratio: N/A
Mohs Hardness: N/A
Vickers Hardness: N/A
Brinell Hardness: N/A
Speed of Sound: (20 °C) 16,200 m·s-1
Pauling Electronegativity: 1.9
Sanderson Electronegativity: N/A
Allred Rochow Electronegativity: 1.36
Mulliken-Jaffe Electronegativity: N/A
Allen Electronegativity: N/A
Pauling Electropositivity: 2.1
Reflectivity (%): N/A
Refractive Index: N/A
Electrons: 43
Protons: 43
Neutrons: 55
Electron Configuration: [Kr] 4d5 5s2
Atomic Radius: 1.36 pm
Atomic Radius,
non-bonded (Å):
2.16
Covalent Radius: 147±7 pm
Covalent Radius (Å): 1.38
Van der Waals Radius: N/A
Oxidation States: 7, 6, 5, 4, 3, 2, 1, -1, -3 (strongly acidic oxide)
Phase: Solid
Crystal Structure: hexagonal close-packed
Magnetic Ordering: paramagnetic
Electron Affinity (kJ·mol-1) 53.048
1st Ionization Energy: 702.42 kJ·mol-1
2nd Ionization Energy: 702.42 kJ·mol-1
3rd Ionization Energy: 2850.20 kJ·mol-1
CAS Number: 7440-26-8
EC Number: N/A
MDL Number: N/A
Beilstein Number: N/A
SMILES Identifier: [Re]
InChI Identifier: InChI=1S/Tc
InChI Key: GKLVYJBZJHMRIY-UHFFFAOYSA-N
PubChem CID: N/A
ChemSpider ID: 22396
Earth - Total: N/A
Mercury - Total: N/A
Venus - Total: N/A
Earth - Seawater (Oceans), ppb by weight: N/A
Earth - Seawater (Oceans), ppb by atoms: N/A
Earth -  Crust (Crustal Rocks), ppb by weight: N/A
Earth -  Crust (Crustal Rocks), ppb by atoms: N/A
Sun - Total, ppb by weight: N/A
Sun - Total, ppb by atoms: N/A
Stream, ppb by weight: N/A
Stream, ppb by atoms: N/A
Meterorite (Carbonaceous), ppb by weight: N/A
Meterorite (Carbonaceous), ppb by atoms: N/A
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: Carlo Perrier and Emilio Segrè
Discovery Date: 1937
First Isolation: Carlo Perrier and Emilio Segrè (1937)

Technetium Isotopes

Technetium has no stable isotopes (all are radioactive).

Nuclide Isotopic Mass Half-Life Mode of Decay Nuclear Spin Magnetic Moment Binding Energy (MeV) Natural Abundance
(% by atom)
85Tc84.94883(43)#<110 nsß+ to 85Mo; p to 84Mo; ß+ + p to 84Nb1/2-#N/A686.89-
86Tc85.94288(32)#55(6) msß+ to 86Mo(0+)N/A700.55-
87Tc86.93653(32)#2.18(16) sß+ to 87Mo1/2-#N/A714.22-
88Tc87.93268(22)#5.8(2) sß+ to 88Mo(2,3)N/A726.03-
89Tc88.92717(22)#12.8(9) sß+ to 89Mo(9/2+)N/A738.77-
90Tc89.92356(26)8.7(2) sß+ to 90Mo1+N/A750.57-
91Tc90.91843(22)3.14(2) minß+ to 91Mo(9/2)+N/A763.31-
92Tc91.915260(28)4.25(15) minß+ to 92Mo(8)+N/A774.18-
93Tc92.910249(4)2.75(5) hEC to 93Mo9/2+6.26786.92-
94Tc93.909657(5)293(1) minEC to 94Mo7+5.08795.93-
95Tc94.907657(6)20.0(1) hEC to 95Mo9/2+5.89805.87-
96Tc95.907871(6)4.28(7) dEC to 96Mo7+5.04813.95-
97Tc96.906365(5)2.6E+6 yEC to 97Mo9/2+N/A822.96-
98Tc97.907216(4)4.2(3)E+6 yß- to 98Ru(6)+N/A830.11-
99Tc98.9062547(21)2.111(12)E+5 yß- to 99Ru9/2+5.6847839.12-
100Tc99.9076578(24)15.8(1) sß- to 100Ru; EC to 100Mo1+N/A846.26-
101Tc100.907315(26)14.22(1) minß- to 101Ru9/2+N/A860.86-
102Tc101.909215(10)5.28(15) sß- to 102Ru1+N/A868.94-
103Tc102.909181(11)54.2(8) sß- to 103Ru5/2+N/A877.02-
104Tc103.91145(5)18.3(3) minß- to 104Ru(3+)#N/A875.78-
105Tc104.91166(6)7.6(1) minß- to 105Ru(3/2-)N/A883.86-
106Tc105.914358(14)35.6(6) sß- to 106Ru(1,2)N/A891.94-
107Tc106.91508(16)21.2(2) sß- to 107Ru(3/2-)N/A900.02-
108Tc107.91846(14)5.17(7) sß- to 108Ru(2)+N/A908.1-
109Tc108.91998(10)860(40) msß- to 109Ru; ß- + n to 108Ru3/2-#N/A916.18-
110Tc109.92382(8)0.92(3) sß- to 110Ru; ß- + n to 109Ru(2+)N/A914.94-
111Tc110.92569(12)290(20) msß- to 111Ru; ß- + n to 110Ru3/2-#N/A923.02-
112Tc111.92915(13)290(20) msß- to 112Ru; ß- + n to 111Ru2+#N/A931.1-
113Tc112.93159(32)#170(20) msß- to 113Ru3/2-#N/A929.86-
114Tc113.93588(64)#150(30) msß- to 114Ru2+#N/A937.94-
115Tc114.93869(75)#100# ms [>300 ns]ß- to 115Ru3/2-#N/A946.02-
116Tc115.94337(75)#90# ms [>300 ns]Unknown2+#N/A944.78-
117Tc116.94648(75)#40# ms [>300 ns]Unknown3/2-#N/A952.86-
118Tc117.95148(97)#30# ms [>300 ns]Unknown2+#N/A951.62-
Technetium (Tc) Elemental Symbol

Recent Research & Development for Technetium

  • Rhenium and Technetium Complexes with Pentadentate Thiocarbamoylbenzamidines: Steps toward Bioconjugation.2015 Jun 15Nguyen HH, Pham CT, Abram U. Inorg Chem. 2015 Jun 15
  • INTRA-ARTERIAL HEPATIC SPECT/CT IMAGING USING TECHNETIUM-99M MACRO-AGGREGATED ALBUMIN IN PREPARATION FOR RADIOEMBOLIZATION.2015 Jun 18Gates VL, Singh N, Lewandowski R, Spies SM, Salem R. J Nucl Med. 2015 Jun 18
  • Clinical application of autologous technetium-99m-labelled eosinophils to detect focal eosinophilic inflammation in the lung.2015 Jun 24Loutsios C, Farahi N, Simmonds R, Cullum I, Gillett D, Solanki C, Solanki K, Buscombe J, Condliffe AM, Peters AM, Chilvers ER. Thorax. 2015 Jun 24
  • Technetium-99 m labeling and evaluation of olsalazine: a novel agent for ulcerative colitis imaging.2015 Jun 30El-Kawy OA, Ibrahim IT, Farah K. J Labelled Comp Radiopharm. 2015 Jun 30
  • 99m-Technetium binding site in bone marrow mononuclear cells.2015 Jun 4Suhett GD, de Souza SA, Carvalho AB, de Pinho Rachid R, da Cunha-E-Silva NL, de Carvalho AC, da Fonseca LM, dos Santos Goldenberg RC, Gutfilen B. Stem Cell Res Ther. 2015 Jun 4
  • Preparation and biodistribution of 1-((2-methoxyphenyl) piperazine)ferrocenecarboxamide labeled with technetium-99m as a potential brain receptor imaging agent.2015 Jun 5Saied NM, Mejri N, Aissi RE, Benoist E, Saidi M. Eur J Med Chem. 2015 Jun 5
  • Technetium-99m-labeled annexin V imaging for detecting prosthetic joint infection in a rabbit model.2015 MayTang C, Wang F, Hou Y, Lu S, Tian W, Xu Y, Jin C, Wang L. J Biomed Res. 2015 May
  • Uptake of Technetium-99m DTPA in Bone Metastases from Renal Cancer.2015 May 25Wang T, Zhao J, Xing Y. Clin Nucl Med. 2015 May 25
  • Preparation and Biodistribution of Technetium-99m-Labeled Bis-Misonidazole (MISO) as an Imaging Agent for Tumour Hypoxia.2015 May 4Wang F, Fan DI, Qian J, Zhang Z, Zhu J, Chen J. Med Chem. 2015 May 4
  • Hybrid Single-Photon Emission Computed Tomography/Computed Tomography Imaging Features of Tumoral Calcinosis in Technetium-99m Methylene Diphosphonate Bone Scintigraphy.2015 May-AugKamaleshwaran KK, Asokumar P, Malaikkal A, Mohanan V, Shinto AS. World J Nucl Med. 2015 May-Aug