GADOLINIUM

introduction

Numéro atomique: 64
Groupe: Aucun
Poids atomique: 157.25
Période: 6
Numero CAS: 7440-54-2

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

Gadolinia, the oxide of gadolinium, was separated by Marignac in 1880 and Lecoq de Boisbaudran independently isolatedthe element from Mosander’s “yttria” in 1886. The element was named for the mineral gadolinite from which this rare earth was originally obtained.Gadolinium is found in several other minerals, including monazite and bastnasite, which are of commercial importance. The element has been isolatedonly in recent years. With the development of ion-exchange and solvent extraction techniques, the availability and price of gadolinium and the otherrare-earth metals have greatly improved. Thirty isotopes and isomers of gadolinium are now recognized; seven are stable and occur naturally. The metalcan be prepared by the reduction of the anhydrous fluoride with metallic calcium. As with other related rare-earth metals, it is silvery white, has ametallic luster, and is malleable and ductile. At room temperature, gadolinium crystallizes in the hexagonal, close-packed alpha form. Upon heating to1235°C, alpha gadolinium transforms into the beta form, which has a body-centered cubic structure. The metal is relatively stable in dry air, but in moist airit tarnishes with the formation of a loosely adhering oxide film which spalls off and exposes more surface to oxidation. The metal reacts slowly withwater and is soluble in dilute acid. Gadolinium has the highest thermal neutron capture cross-section of any known element (49,000 barns). Naturalgadolinium is a mixture of seven isotopes. Two of these, 155Gd and 157Gd, have excellent capture characteristics, but they are present naturally in lowconcentrations. As a result, gadolinium has a very fast burnout rate and has limited use as a nuclear control rod material. It has been used in makinggadolinium yttrium garnets, which have microwave applications. Compounds of gadolinium are used in making phosphors for color TV tubes. Themetal has unusual superconductive properties. As little as 1% gadolinium has been found to improve the workability and resistance of iron, chromium,and related alloys to high temperatures and oxidation. Gadolinium ethyl sulfate has extremely low noise characteristics and may find use in duplicatingthe performance of amplifiers, such as the maser. The metal is ferromagnetic. Gadolinium is unique for its high magnetic moment and for its specialCurie temperature (above which ferromagnetism vanishes) lying just at room temperature. This suggests uses as a magnetic component that senseshot and cold. The price of the metal is $2/g (99.9% purity). 1

• "Night-vision goggles require...gadolinium" 2
• "Gadolinium also serves as a contrast agent in magnetic resonance imaging, or MRI, helping surgeons distinguish diseased from healthy tissue." 3

Propriétés physiques

Point de fusion:4*  1313 °C = 1586.15 K = 2395.4 °F
Point d'ébullition:4* 3273 °C = 3546.15 K = 5923.4 °F
sublimation point:4 
Triple point:4 
Point critique:4 
Densité:5  7.90 g/cm3

* - at 1 atm

Configuration de l'électron

Configuration de l'électron:  *[Xe] 6s2 4f8
Bloque: f
Plus haut niveau d'énergie occupés: 6
Électrons de valence: 2

Nombres quantiques:

n = 4
ℓ = 3
m = -3
ms = -½

Bonding

Électronégativité (échelle de Pauling):6 1.20
Electropositivity (échelle de Pauling): 2.8
Fonction de travail:7 5.1 eV = 8.1702E-19 J

ionisation potentiel   eV 8  kJ/mol  
1 6.1501    593.4
ionisation potentiel   eV 8  kJ/mol  
2 12.09    1166.5
ionisation potentiel   eV 8  kJ/mol  
3 20.63    1990.5
4 44    4245.4

Thermochimie

Chaleur spécifique: 0.236 J/g°C 9 = 37.111 J/mol°C = 0.056 cal/g°C = 8.870 cal/mol°C
Conductivité thermique: 10.6 (W/m)/K, 27°C 10
Température de fusion: 10.05 kJ/mol 11 = 63.9 J/g
Chaleur de vaporisation: 359.4 kJ/mol 12 = 2285.5 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 16.27 68.07368 0 0
(g) 95.0 397.48 46.42 194.22128 86.0 359.824

isotopes

Nuclide Masse 14 Demi vie 14 Spin nucléaire 14 Énergie de liaison
134Gd 133.95537(43)# 0.4# s 0+ 1,078.06 MeV
135Gd 134.95257(54)# 1.1(2) s 3/2- 1,086.13 MeV
136Gd 135.94734(43)# 1# s [>200 ns] 1,103.52 MeV
137Gd 136.94502(43)# 2.2(2) s 7/2+# 1,111.59 MeV
138Gd 137.94012(21)# 4.7(9) s 0+ 1,119.66 MeV
139Gd 138.93824(21)# 5.7(3) s 9/2-# 1,137.05 MeV
140Gd 139.93367(3) 15.8(4) s 0+ 1,145.12 MeV
141Gd 140.932126(21) 14(4) s (1/2+) 1,153.19 MeV
142Gd 141.92812(3) 70.2(6) s 0+ 1,170.57 MeV
143Gd 142.92675(22) 39(2) s (1/2)+ 1,178.65 MeV
144Gd 143.92296(3) 4.47(6) min 0+ 1,186.72 MeV
145Gd 144.921709(20) 23.0(4) min 1/2+ 1,194.79 MeV
146Gd 145.918311(5) 48.27(10) d 0+ 1,212.17 MeV
147Gd 146.919094(3) 38.06(12) h 7/2- 1,220.25 MeV
148Gd 147.918115(3) 74.6(30) a 0+ 1,228.32 MeV
149Gd 148.919341(4) 9.28(10) d 7/2- 1,236.39 MeV
150Gd 149.918659(7) 1.79(8)E+6 a 0+ 1,244.46 MeV
151Gd 150.920348(4) 124(1) d 7/2- 1,243.22 MeV
152Gd 151.9197910(27) 1.08(8)E+14 a 0+ 1,260.60 MeV
153Gd 152.9217495(27) 240.4(10) d 3/2- 1,259.36 MeV
154Gd 153.9208656(27) STABLE 0+ 1,267.43 MeV
155Gd 154.9226220(27) STABLE 3/2- 1,275.50 MeV
156Gd 155.9221227(27) STABLE 0+ 1,283.57 MeV
157Gd 156.9239601(27) STABLE 3/2- 1,291.64 MeV
158Gd 157.9241039(27) STABLE 0+ 1,299.72 MeV
159Gd 158.9263887(27) 18.479(4) h 3/2- 1,307.79 MeV
160Gd 159.9270541(27) STABLE 0+ 1,315.86 MeV
161Gd 160.9296692(29) 3.646(3) min 5/2- 1,323.93 MeV
162Gd 161.930985(5) 8.4(2) min 0+ 1,322.69 MeV
163Gd 162.93399(32)# 68(3) s 7/2+# 1,330.76 MeV
164Gd 163.93586(43)# 45(3) s 0+ 1,338.83 MeV
165Gd 164.93938(54)# 10.3(16) s 1/2-# 1,346.90 MeV
166Gd 165.94160(64)# 4.8(10) s 0+ 1,345.66 MeV
167Gd 166.94557(64)# 3# s 5/2-# 1,353.73 MeV
168Gd 167.94836(75)# 300# ms 0+ 1,361.80 MeV
169Gd 168.95287(86)# 1# s 7/2-# 1,360.56 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: phosphates 15
Terre - Seawater: 0.0000007 mg/L 16
Terre -  Croûte:  6.2 mg/kg = 0.00062% 16
Terre -  Total:  286 ppb 17
Planète Mercure) -  Total:  220 ppb 17
Vénus -  Total:  300 ppb 17
chondrites - Total: 0.34 (relative to 106 atoms of Si) 18

composés

Information de sécurité


Fiche signalétique - ACI Alloys, Inc.

Pour plus d'informations

Liens externes:

Les magazines:
(1) Folger, Tim. The Secret Ingredients of Everything. National Geographic, June 2011, pp 136-145.

Sources

(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:12-4:13.
(2) - Folger, Tim. The Secret Ingredients of Everything. National Geographic, June 2011, p 140.
(3) - Folger, Tim. The Secret Ingredients of Everything. National Geographic, June 2011, p 140.
(4) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:132.
(5) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 4:39-4:96.
(6) - Dean, John A. Lange's Handbook of Chemistry, 11th ed.; McGraw-Hill Book Company: New York, NY, 1973; p 4:8-4:149.
(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.