TANTALIO

Introducción

Número atómico: 73
Grupo: 5 or V B
Peso atomico: 180.9479
Período: 6
Número CAS: 7440-25-7

Clasificación

chalcogen
halógeno
Gas noble
Lantanoides
Actinoides
Elemento de tierras raras
Platino Metal Group
transuranium
No hay isótopos estables
Sólido
Líquido
Gas
Sólido (Predicho)

Descripción • Usos / Función

Discovered in 1802 by Ekeberg, but many chemists thought niobium and tantalum were identical elements until Rose,in 1844, and Marignac, in1866, showed that niobic and tantalic acids were two different acids. The early investigators only isolated the impure metal.The first relatively pure ductile tantalum was produced by von Bolton in 1903. Tantalum occurs principally in the mineral columbite-tantalite (Fe,Mn)(Nb, Ta)2O6. Tantalum ores are found in Australia, Brazil, Mozambique, Thailand, Portugal, Nigeria, Zaire, and Canada. Separation of tantalumfrom niobium requires several complicated steps. Several methods are used to commercially produce the element, including electrolysis of moltenpotassium fluorotantalate, reduction of potassium fluorotantalate with sodium, or reacting tantalum carbide with tantalum oxide. Thirty four isotopesand isomers of tantalum are known to exist. Natural tantalum contains two isotopes, one of which is radioactive with a very long half-life. Tantalumis a gray, heavy, and very hard metal. When pure, it is ductile and can be drawn into fine wire, which is used as a filament for evaporating metals suchas aluminum. Tantalum is almost completely immune to chemical attack at temperatures below 150°C, and is attacked only by hydrofluoric acid, acidicsolutions containing the fluoride ion, and free sulfur trioxide. Alkalis attack it only slowly. At high temperatures, tantalum becomes much more reactive.The element has a melting point exceeded only by tungsten and rhenium. Tantalum is used to make a variety of alloys with desirable properties suchas high melting point, high strength, good ductility, etc. Scientists at Los Alamos have produced a tantalum carbide graphite composite material, whichis said to be one of the hardest materials ever made. The compound has a melting point of 3738°C. Tantalum has good “gettering” ability at hightemperatures, and tantalum oxide films are stable and have good rectifying and dielectric properties. Tantalum is used to make electrolytic capacitorsand vacuum furnace parts, which account for about 60% of its use. The metal is also widely used to fabricate chemical process equipment, nuclearreactors, and aircraft and missile parts. Tantalum is completely immune to body liquids and is a nonirritating metal. It has, therefore, found wide usein making surgical appliances. Tantalum oxide is used to make special glass with high index of refraction for camera lenses. The metal has many otheruses. The price of (99.9%) tantalum is about $900/kg. The metal of 99.995% purity sells for about $2/g. 1

• "A number of transition metals (Ti, Zr, Hf, V, Nb, Ta, Mo, W) form interstitial carbides of composition MC and, in some cases, M2C. These carbides have extremely high melting points; they are very hard, and they are good electrical conductors." 2

Propiedades físicas

Punto de fusion:3*  3017 °C = 3290.15 K = 5462.6 °F
Punto de ebullición:3* 5458 °C = 5731.15 K = 9856.4 °F
Punto de sublimación:3 
Triple punto:3 
Punto crítico:3 
Densidad:4  16.4 g/cm3

* - at 1 atm

Configuración electronica

Configuración electronica: [Xe] 6s2 4f14 5d3
Bloquear: d
Ocupado más alto nivel de energía: 6
Electrones de valencia: 

Números cuánticos:

n = 5
ℓ = 2
m = 0
ms = +½

Vinculación

electronegatividad (escala de Pauling):5 1.5
Electropositivity (escala de Pauling): 2.5
Afinidad electronica:6 0.322 eV
estados de oxidación: +5
Función del trabajo:7 4.22 eV = 6.76044E-19 J

potencial de ionización   eV 8  kJ/mol  
potencial de ionización   eV 8  kJ/mol  
potencial de ionización   eV 8  kJ/mol  
1 7.5496    728.4

termoquímica

Calor especifico: 0.140 J/g°C 9 = 25.333 J/mol°C = 0.033 cal/g°C = 6.055 cal/mol°C
Conductividad térmica: 57.5 (W/m)/K, 27°C 10
Calor de fusión: 31.6 kJ/mol 11 = 174.6 J/g
Calor de vaporización: 743 kJ/mol 12 = 4106.2 J/g
Estado de la materia Entalpía de formación (ΔHf°)13 entropía (S°)13 Energía libre de Gibbs (ΔGf°)13
(kcal/mol) (kJ/mol) (cal/K) (J/K) (kcal/mol) (kJ/mol)
(s) 0 0 9.92 41.50528 0 0
(g) 186.9 781.9896 44.241 185.104344 176.7 739.3128

isótopos

nucleido Masa 14 Media vida 14 spin nuclear 14 Energía de unión
155Ta 154.97459(54)# 13(4) μs [12(+4-3) μs] (11/2-) 1,221.89 MeV
156Ta 155.97230(43)# 144(24) ms (2-) 1,229.96 MeV
157Ta 156.96819(22) 10.1(4) ms 1/2+ 1,247.34 MeV
158Ta 157.96670(22)# 49(8) ms (2-) 1,255.41 MeV
159Ta 158.963018(22) 1.04(9) s (1/2+) 1,263.49 MeV
160Ta 159.96149(10) 1.70(20) s (2#)- 1,271.56 MeV
161Ta 160.95842(6)# 3# s 1/2+# 1,288.94 MeV
162Ta 161.95729(6) 3.57(12) s 3+# 1,297.01 MeV
163Ta 162.95433(4) 10.6(18) s 1/2+# 1,305.09 MeV
164Ta 163.95353(3) 14.2(3) s (3+) 1,313.16 MeV
165Ta 164.950773(19) 31.0(15) s 5/2-# 1,321.23 MeV
166Ta 165.95051(3) 34.4(5) s (2)+ 1,329.30 MeV
167Ta 166.94809(3) 1.33(7) min (3/2+) 1,346.69 MeV
168Ta 167.94805(3) 2.0(1) min (2-,3+) 1,354.76 MeV
169Ta 168.94601(3) 4.9(4) min (5/2+) 1,362.83 MeV
170Ta 169.94618(3) 6.76(6) min (3)(+#) 1,370.90 MeV
171Ta 170.94448(3) 23.3(3) min (5/2-) 1,378.97 MeV
172Ta 171.94490(3) 36.8(3) min (3+) 1,387.04 MeV
173Ta 172.94375(3) 3.14(13) h 5/2- 1,395.11 MeV
174Ta 173.94445(3) 1.14(8) h 3+ 1,403.19 MeV
175Ta 174.94374(3) 10.5(2) h 7/2+ 1,411.26 MeV
176Ta 175.94486(3) 8.09(5) h (1)- 1,419.33 MeV
177Ta 176.944472(4) 56.56(6) h 7/2+ 1,427.40 MeV
178Ta 177.945778(16) 9.31(3) min 1+ 1,435.47 MeV
179Ta 178.9459295(23) 1.82(3) a 7/2+ 1,443.54 MeV
180Ta 179.9474648(24) 8.152(6) h 1+ 1,451.61 MeV
181Ta 180.9479958(19) ESTABLE 7/2+ 1,459.68 MeV
182Ta 181.9501518(19) 114.43(3) d 3- 1,458.44 MeV
183Ta 182.9513726(19) 5.1(1) d 7/2+ 1,466.51 MeV
184Ta 183.954008(28) 8.7(1) h (5-) 1,474.58 MeV
185Ta 184.955559(15) 49.4(15) min (7/2+)# 1,482.65 MeV
186Ta 185.95855(6) 10.5(3) min (2-,3-) 1,490.73 MeV
187Ta 186.96053(21)# 2# min [>300 ns] 7/2+# 1,489.48 MeV
188Ta 187.96370(21)# 20# s [>300 ns] 1,497.55 MeV
189Ta 188.96583(32)# 3# s [>300 ns] 7/2+# 1,505.63 MeV
190Ta 189.96923(43)# 0.3# s 1,513.70 MeV
Los valores marcados con # no son puramente derivan de los datos experimentales, pero al menos en parte, de las tendencias sistemáticas. Hace girar con débiles argumentos de asignación se incluyen entre paréntesis. 14

Abundancia

Tierra - Los compuestos de origen: oxides 15
Tierra - Agua de mar: 0.000002 mg/L 16
Tierra -  Corteza:  2 mg/kg = 0.0002% 16
Tierra -  Total:  23.3 ppb 17
Planeta mercurio) -  Total:  17.9 ppb 17
Venus -  Total:  24.4 ppb 17
condritas - Total: 0.016 (relative to 106 atoms of Si) 18

Compuestos

Precios





Información de seguridad


Ficha de datos de seguridad de materiales - ACI Alloys, Inc.

Para más información

Enlaces externos:

Fuentes

(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:30.
(2) - Jolly, William L. The Chemistry of the Non-Metals; Prentice-Hall: Englewood Cliffs, New Jersey, 1966; p 119.
(3) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:132.
(4) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 4:39-4:96.
(5) - Dean, John A. Lange's Handbook of Chemistry, 11th ed.; McGraw-Hill Book Company: New York, NY, 1973; p 4:8-4:149.
(6) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 10:147-10:148.
(7) - Speight, James. Lange's Handbook of Chemistry, 16th ed.; McGraw-Hill Professional: Boston, MA, 2004; p 1:132.
(8) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 10:178 - 10:180.
(9) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:133.
(10) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:193, 12:219-220.
(11) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:123-6:137.
(12) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:107-6:122.
(13) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(14) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).
(15) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 965.
(16) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 14:17.
(17) - Morgan, John W. and Anders, Edward, Proc. Natl. Acad. Sci. USA 77, 6973-6977 (1980)
(18) - Brownlow, Arthur. Geochemistry; Prentice-Hall, Inc.: Englewood Cliffs, NJ, 1979, pp 15-16.