WebElements Periodic Table of the Elements | Technetium

Technetium: the essentials

Since its discovery, searches for the element technetium in terrestrial materials have been made without success. Technetium has been found in the spectrum of S-, M-, and N-type stars, and its presence in stellar matter is leading to new theories of the production of heavy elements in the stars.

Technetium is a silvery-grey metal that tarnishes slowly in moist air. Until 1960, technetium was available only in small amounts. The chemistry of technetium is related to that of rhenium.

Table: basic information about and classifications of technetium.
Name: Technetium Symbol: Tc Atomic number: 43 Atomic weight: [ 98 ] Standard state: solid at 298 K CAS Registry ID: 7440-26-8	Group in periodic table: 7 Group name: (none) Period in periodic table: 5 Block in periodic table: d-block Colour: silvery grey metallic Classification: Metallic

Technetium: historical information

Technetium was discovered by Carlo Perrier, Emilio Segre at 1937 in Italy. Origin of name: from the Greek word "technikos" meaning "artificial".

Element 43 (technetium) was predicted on the basis of the periodic table by Mendeleev. He suggested that it should be very similar to manganese and gave it the name ekamanganese. Technetium was erroneously reported as having been discovered in 1925, at which time it was named masurium. The element was actually discovered by C. Perrier and Emilio Gino Segre in Italy in 1937. It was found in a sample of molybdenum bombarded by deuterons. Technetium was the first element to be produced artificially and all its isotopes are radioactive. It is named after the Greek technetos, artificial.

Technetium: physical properties

Melting point: 2430 [or 2157 °C (3915 °F)] K
Boiling point: 4538 [or 4265 °C (7709 °F)] K
Density of solid: 11500 kg m^-3

Ground state electron configuration: [Kr].4d⁶.5s¹
Shell structure: 2.8.18.14.1
Term symbol: ⁶S_5/2
Pauling electronegativity: 1.9 (Pauling units)
First ionisation energy: 702 kJ mol^-1
Second ionisation energy: 1470 kJ mol^-1

Isolation

Isolation: it is never necessary to make a sample of techntium anywhere other than specialist laboratories. This is because technetium is radioactive. Technetium is a byproduct of the nuclear industry and is a product of uranium decay. Alternatively it can be made by the bombardment of molydenum targets with deuterium nuclei.

Because of the scale of the nuclear industry it is possible to make quite large quantities of technetium (kilograms). The metal itself may be made by the reaction of the sulphide Tc₂S₇ with hydrogen at 1100°C or of the pertechnate NH₄TcO₄ with hydrogen.

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Cr	Mn	Fe
Mo	Tc	Ru
W	Re	Os

Technetium	Technétium
Technetium	Technetium
Tecneto	Tecnecio
Teknetium	Tecnécio

Technetium
- Essential data: names, symbol, atomic number, and atomic weight; block, period, and group in periodic table; description; standard state; registry number; and isolation
- History: meaning of name; discovery; and history of the element
- Uses
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Technetium around us
- Geology: Abundance of elements in the universe; the sun; meteorites; Earth's crust; oceans; and streams
- Biology: Abundance in humans; biological role; and health hazards)
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Chemistry and compounds
- Compounds: halides, oxides, sulfides, hydrides, and complexes; lattice energies; and reduction potentials
- Reactions of technetium: reactions of technetium with air; water; halogens; acids; and bases
- Electronegativities: Pauling; Sanderson; Allred Rochow; Mulliken-Jaffe; and Allen
- Bond enthalpies of diatomic species
- Lattice energies
Element properties
- Physics properties: Boiling point; melting point; density; molar volume; thermal conductivity; and electrical resistivity; bulk modulus; critical temperature; superconductivity temperature; hardness (mineralogical, Brinell, and Vickers); linear expansion coefficient; Poisson's ratio; reflectivity; refractive index; rigidity modulus; Young's modulus; velocity of sound
- Crystal structure
- Thermochemistry: enthalpies of atomization, fusion, and vaporization; thermodynamic properties
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Atom properties
- Electron shell properties: Electronic configuration; term symbol; electron affinity; ionization energies; and atomic spectra
- Atom sizes: atomic radius; Shannon and Pauling ionic radii; covalent radius; metallic radius; element bond length; and Van der Waals radius
- Atomic orbital properties: effective nuclear charge; electron binding energies; and valence orbital radii maxima
Nuclear properties
- Isotopes: isotope abundances; radioactive isotopes; isotope masses; nuclear spins; and nuclear magnetic moment
- NMR properties: frequencies; isotopes; magnetogyric ratios; quadrupole moments; receptivities; and relative sensitivities
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1	2															3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18

1 H																															2 He
3 Li	4 Be																									5 B	6 C	7 N	8 O	9 F	10 Ne
11 Na	12 Mg																									13 Al	14 Si	15 P	16 S	17 Cl	18 Ar
19 K	20 Ca															21 Sc	22 Ti	23 V	24 Cr	25 Mn	26 Fe	27 Co	28 Ni	29 Cu	30 Zn	31 Ga	32 Ge	33 As	34 Se	35 Br	36 Kr
37 Rb	38 Sr															39 Y	40 Zr	41 Nb	42 Mo	43 Tc	44 Ru	45 Rh	46 Pd	47 Ag	48 Cd	49 In	50 Sn	51 Sb	52 Te	53 I	54 Xe
55 Cs	56 Ba	57 La	58 Ce	59 Pr	60 Nd	61 Pm	62 Sm	63 Eu	64 Gd	65 Tb	66 Dy	67 Ho	68 Er	69 Tm	70 Yb	71 Lu	72 Hf	73 Ta	74 W	75 Re	76 Os	77 Ir	78 Pt	79 Au	80 Hg	81 Tl	82 Pb	83 Bi	84 Po	85 At	86 Rn
87 Fr	88 Ra	89 Ac	90 Th	91 Pa	92 U	93 Np	94 Pu	95 Am	96 Cm	97 Bk	98 Cf	99 Es	100 Fm	101 Md	102 No	103 Lr	104 Rf	105 Db	106 Sg	107 Bh	108 Hs	109 Mt	110 Ds	111 Rg	112 Cn	113 Uut	114 Fl	115 Uup	116 Lv	117 Uus	118 Uuo

Technetium

Technetium: the essentials

Technetium: historical information

Technetium: physical properties

Technetium: orbital properties

Isolation

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