TECNECIO

Introducción

Número Atómico: 43
Grupo: 7 or VII B
Peso Atómico: 98
Periodo: 5
Número CAS: 7440-26-8

Clasificación

Anfígeno
Halógeno
Gases nobles
Lantánido
Actínido
Tierras Raras
Platino Metal Grupo
Transuránicos
No Isótopos Estables
Sólido
Líquido
Gas
Sólido (Predicción)

Descripción

Element 43 was predicted on the basis of the periodic table, and was erroneously reported as having been discovered in 1925, at which time it was named masurium. The element was actually discovered by Perrier and Segre in Italy in 1937. It was found in a sample of molybdenum, which was bombarded by deuterons in the Berkeley cyclotron, and which E. Lawrence sent to these investigators. Technetium was the first element to be produced artificially. Since its discovery, searches for the element in terrestrial materials have been made without success. If it does exist, the concentration must be very small. 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. Thirty one isotopes and isomers of technetium, with atomic masses ranging from 86 to 113, are known. 97Tc has a half-life of 2.6 X 10^6 years. 98Tc has a half-life of 4.2 X 10^6 years. The isomeric isotope 95mTc, with a half-life of 61 days, is useful for tracer work, as it produces energetic gamma rays. Technetium metal has been produced in kilogram quantities. The metal was first prepared by passing hydrogen gas at 1100°C over Tc2S7. It is now conveniently prepared by the reduction of ammonium pertechnetate with hydrogen. Technetium is a silvery-gray metal that tarnishes slowly in moist air. Until 1960, technetium was available only in small amounts and the price was as high as $2800/g. It is now commercially available to holders of O.R.N.L. permits at a price of $74/g plus packing charges. The chemistry of technetium is said to be similar to that of rhenium. Technetium dissolves in nitric acid, aqua regia, and conc. sulfuric acid, but is not soluble in hydrochloric acid of any strength. The element is a remarkable corrosion inhibitor for steel. It is reported that mild carbon steels may be effectively protected by as little as 55 ppm of KTcO4 in aerated distilled water at temperatures up to 250°C. This corrosion protection is limited to closed systems, since technetium is radioactive and must be confined. 99Tc has a specific activity of 6.2 X 10^8 Bq/g. Activity of this level must not be allowed to spread. 99Tc is a contamination hazard and should be handled in a glove box. The metal is an excellent superconductor at 11 K and below. 1

Magnitudes Físicas

Punto de Fusión:2*  2157 °C = 2430.15 K = 3914.6 °F
Punto de Ebullición:2* 4265 °C = 4538.15 K = 7709 °F
Punto de Sublimación:2 
Punto Triple:2 
Punto Crítico:2 
Densidad:3  11 g/cm3

* - at 1 atm

Configuración Electrónica

Configuración Electrónica: [Kr] 5s2 4d5
Bloque: d
Nivel Más Alto de Energía Ocupados: 5
Electrones de Valencia: 2

Números Cuánticos:

n = 4
ℓ = 2
m = 2
ms = +½

Enlace Químico

Electronegatividad (Escala de Pauling):4 2.10
Electropositivity (Escala de Pauling): 1.9
Afinidad Electrónica:5 0.55 eV
Estados de Oxidación: +7,4,6

Energía de Ionización   eV 6  kJ/mol  
1 7.28    702.4
Energía de Ionización   eV 6  kJ/mol  
1 7.28    702.4
2 15.26    1472.4
Energía de Ionización   eV 6  kJ/mol  
3 29.54    2850.2

Termoquímica

Capacidad Calorífica: 
Conductividad Térmica: 50.6 (W/m)/K, 27ºC 7
Entalpía de Fusión: 24 kJ/mol 8 = 244.9 J/g
Entalpía de Vaporización: 660 kJ/mol 9 = 6734.7 J/g
Estado de Agregación de la Materia Entalpía de Formación (ΔHf°)10 Entropía (S°)10 Energía Libre de Gibbs (ΔGf°)10
(kcal/mol) (kJ/mol) (cal/K) (J/K) (kcal/mol) (kJ/mol)
(s) 0 0 8.00 33.472 0 0

Isótopos

Nucleido Masa 11 Periodo de Semidesintegración 11 Espín 11 Energía de enlace nuclear
100Tc 99.9076578(24) 15.8(1) s 1+ 846.26 MeV
101Tc 100.907315(26) 14.22(1) min 9/2+ 860.86 MeV
102Tc 101.909215(10) 5.28(15) s 1+ 868.94 MeV
103Tc 102.909181(11) 54.2(8) s 5/2+ 877.02 MeV
104Tc 103.91145(5) 18.3(3) min (3+)# 875.78 MeV
105Tc 104.91166(6) 7.6(1) min (3/2-) 883.86 MeV
106Tc 105.914358(14) 35.6(6) s (1,2) 891.94 MeV
107Tc 106.91508(16) 21.2(2) s (3/2-) 900.02 MeV
108Tc 107.91846(14) 5.17(7) s (2)+ 908.10 MeV
109Tc 108.91998(10) 860(40) ms 3/2-# 916.18 MeV
110Tc 109.92382(8) 0.92(3) s (2+) 914.94 MeV
111Tc 110.92569(12) 290(20) ms 3/2-# 923.02 MeV
112Tc 111.92915(13) 290(20) ms 2+# 931.10 MeV
113Tc 112.93159(32)# 170(20) ms 3/2-# 929.86 MeV
114Tc 113.93588(64)# 150(30) ms 2+# 937.94 MeV
115Tc 114.93869(75)# 100# ms [>300 ns] 3/2-# 946.02 MeV
116Tc 115.94337(75)# 90# ms [>300 ns] 2+# 944.78 MeV
117Tc 116.94648(75)# 40# ms [>300 ns] 3/2-# 952.86 MeV
118Tc 117.95148(97)# 30# ms [>300 ns] 2+# 951.62 MeV
85Tc 84.94883(43)# <110 ns 1/2-# 686.89 MeV
86Tc 85.94288(32)# 55(6) ms (0+) 700.55 MeV
87Tc 86.93653(32)# 2.18(16) s 1/2-# 714.22 MeV
88Tc 87.93268(22)# 5.8(2) s (2,3) 726.03 MeV
89Tc 88.92717(22)# 12.8(9) s (9/2+) 738.77 MeV
90Tc 89.92356(26) 8.7(2) s 1+ 750.57 MeV
91Tc 90.91843(22) 3.14(2) min (9/2)+ 763.31 MeV
92Tc 91.915260(28) 4.25(15) min (8)+ 774.18 MeV
93Tc 92.910249(4) 2.75(5) h 9/2+ 786.92 MeV
94Tc 93.909657(5) 293(1) min 7+ 795.93 MeV
95Tc 94.907657(6) 20.0(1) h 9/2+ 805.87 MeV
96Tc 95.907871(6) 4.28(7) d 7+ 813.95 MeV
97Tc 96.906365(5) 2.6E+6 a 9/2+ 822.96 MeV
98Tc 97.907216(4) 4.2(3)E+6 a (6)+ 830.11 MeV
99Tc 98.9062547(21) 2.111(12)E+5 a 9/2+ 839.12 MeV
Los valores marcados con # no se derivan exclusivamente de datos experimentales, pero al menos en parte, de las tendencias sistemáticas. Tiradas con argumentos de asignación débiles están encerrados entre paréntesis. 11

Abundancia

Compuestos

Información Sobre Seguridad


Ficha de Datos de Seguridad - ACI Alloys, Inc.

Idiomas

Afrikáans:   Technetium
Albanés:   Teknec
Armenio:   Տեխնեցիում
Árabe:   تكنيتيوم
Arumano:   Tehnetsiumu
Euskera:   Teknezioa
Bosnio:   Tehnecij
Bretón:   Teknetiom
Búlgaro:   Технеций
Bielorruso:   Тэхнецый
Catalán:   Tecneci
Chino:   锝
Córnico:   Technytyum
Croata:   Tehnecij
Checo:   Technecium
Danés:   Technetium
Neerlandés:   Technetium
Esperanto:   Teknecio
Estonio:   Tehneetsium
Feroés:   Technetium
Finés:   Teknetium
Francés:   Technétium
Friulano: Tecnezi
Frisio:   Technetium
Gallego:   Tecnecio
Georgiano:   ტექნეციუმი
Alemán:   Technetium
Griego:   Τεχνητιο
Hebreo:   טכנתיום
Húngaro:   Technécium
Islandés:   Teknetín
Irlandés:   Teicnéitiam
Italiano:   Tecnezio
Japonés:   テクネチウム
Casubio:   Technet
Kazajo:   Технеций
Coreano:   테크네튬
Letónico:   Tehnecijs
Lituano:   Technecis
Luxemburgués:   Technetium
Macedonio:   Технециум
Malayo:   Teknetium
Maltés:   Teknizjum
Manés:   Çheghnaiçhum
Moksha:   Текнеци
Mongol:   Технеци
Noruego:   Technetium
Occitano:   Tecneci
Osetio:   Технеций
Polaco:   Technet
Portugués:   Tecnécio
Ruso:   Технеций
Gaélico Escocés:   Teicnèitiam
Serbio:   Технициjум
Eslovaco:   Technécium
Español:   Tecnecio
:   Technecis
Suajili:   Tekineti
Sueco:   Teknetium
Tayiko:   Tehneci'
Tailandés:   เทคนีเ ียม
Turco:   Teknesyum
Ucraniano:   Технецій
Uzbeko:   Технеций
Vietnamita:   Tecneti
Galés:   Technetiwm

Véase También

Enlaces Externos:

Revistas:
(1) Raloff, Janet. Desperately Seeking Moly. Science News, September 26, 2009, pp 16-20.

Fuentes

(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:30-4:31.
(2) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:132.
(3) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 4:39-4:96.
(4) - Dean, John A. Lange's Handbook of Chemistry, 11th ed.; McGraw-Hill Book Company: New York, NY, 1973; p 4:8-4:149.
(5) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 10:147-10:148.
(6) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 10:178 - 10:180.
(7) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:193, 12:219-220.
(8) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:123-6:137.
(9) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:107-6:122.
(10) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(11) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).