TANTALE

introduction

Numéro atomique: 73
Groupe: 5 or V B
Poids atomique: 180.9479
Période: 6
Numero CAS: 7440-25-7

Classification

chalcogènes
Halogène
Gaz rare
lanthanides
actinides
Rare Earth Element
Groupe Platine Métal
Transuranium
Pas d'isotopes stables
Solide
Liquide
Gaz
Solide (prédit)

La description • Usages / Fonction

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

Propriétés physiques

Point de fusion:3*  3017 °C = 3290.15 K = 5462.6 °F
Point d'ébullition:3* 5458 °C = 5731.15 K = 9856.4 °F
sublimation point:3 
Triple point:3 
Point critique:3 
Densité:4  16.4 g/cm3

* - at 1 atm

Configuration de l'électron

Configuration de l'électron: [Xe] 6s2 4f14 5d3
Bloque: d
Plus haut niveau d'énergie occupés: 6
Électrons de valence: 

Nombres quantiques:

n = 5
ℓ = 2
m = 0
ms = +½

Bonding

Électronégativité (échelle de Pauling):5 1.5
Electropositivity (échelle de Pauling): 2.5
Electron Affinity:6 0.322 eV
oxydation États: +5
Fonction de travail:7 4.22 eV = 6.76044E-19 J

ionisation potentiel   eV 8  kJ/mol  
ionisation potentiel   eV 8  kJ/mol  
ionisation potentiel   eV 8  kJ/mol  
1 7.5496    728.4

Thermochimie

Chaleur spécifique: 0.140 J/g°C 9 = 25.333 J/mol°C = 0.033 cal/g°C = 6.055 cal/mol°C
Conductivité thermique: 57.5 (W/m)/K, 27°C 10
Température de fusion: 31.6 kJ/mol 11 = 174.6 J/g
Chaleur de vaporisation: 743 kJ/mol 12 = 4106.2 J/g
État de la matière Enthalpie de formation (ΔHf°)13 Entropy (S°)13 Gibbs Free Energy (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

isotopes

Nuclide Masse 14 Demi vie 14 Spin nucléaire 14 Énergie de liaison
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) STABLE 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
Les valeurs marquées # ne sont pas purement dérivées des données expérimentales, mais au moins en partie des tendances systématiques. Spins avec de faibles arguments d'affectation sont entre parenthèses. 14

Abondance

Terre - composés Source: oxides 15
Terre - Seawater: 0.000002 mg/L 16
Terre -  Croûte:  2 mg/kg = 0.0002% 16
Terre -  Total:  23.3 ppb 17
Planète Mercure) -  Total:  17.9 ppb 17
Vénus -  Total:  24.4 ppb 17
chondrites - Total: 0.016 (relative to 106 atoms of Si) 18

composés

prix





Information de sécurité


Fiche signalétique - ACI Alloys, Inc.

Pour plus d'informations

Liens externes:

Sources

(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.