RHODIUM

introduction

Numéro atomique: 45
Groupe: 9 or VIII B
Poids atomique: 102.9055
Période: 5
Numero CAS: 7440-16-6

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

Wollaston discovered rhodium in 1803-4 in crude platinum ore he presumably obtained from South America. Rhodium occurs native withother platinum metals in river sands of the Urals and in North and South America. It is also found with other platinum metals in the copper-nickel sulfideores of the Sudbury, Ontario region. Although the quantity occurring here is very small, the large tonnages of nickel processed make the recoverycommercially feasible. The annual world production of rhodium is only 7 or 8 tons. The metal is silvery white and at red heat slowly changes in airto the sesquioxide. At higher temperatures it converts back to the element. Rhodium has a higher melting point and lower density than platinum. Itsmajor use is as an alloying agent to harden platinum and palladium. Such alloys are used for furnace windings, thermocouple elements, bushings forglass fiber production, electrodes for aircraft spark plugs, and laboratory crucibles. It is useful as an electrical contact material as it has a low electricalresistance, a low and stable contact resistance, and is highly resistant to corrosion. Plated rhodium, produced by electroplating or evaporation, isexceptionally hard and is used for optical instruments. It has a high reflectance and is hard and durable. Rhodium is also used for jewelry, for decoration,and as a catalyst. Forty four isotopes and isomers are now known. Soluble salts should not exceed 0.01 mg/m^3. Rhodium metal (powder) costs about$300/g (99.9% pure). 1

• "An exceedingly thin coating of rhodium is used to give rhodium finish, a warm satiny luster, feebly pink, to jewelry." 2

Propriétés physiques

Point de fusion:3*  1964 °C = 2237.15 K = 3567.2 °F
Point d'ébullition:3* 3695 °C = 3968.15 K = 6683 °F
sublimation point:3 
Triple point:3 
Point critique:3 
Densité:4  12.4 g/cm3

* - at 1 atm

Configuration de l'électron

Configuration de l'électron:  *[Kr] 5s1 4d8
Bloque: d
Plus haut niveau d'énergie occupés: 5
Électrons de valence: 

Nombres quantiques:

n = 4
ℓ = 2
m = 0
ms = -½

Bonding

Électronégativité (échelle de Pauling):5 2.28
Electropositivity (échelle de Pauling): 1.72
Electron Affinity:6 1.137 eV
oxydation États: +3,4,6
Fonction de travail:7 4.98 eV = 7.97796E-19 J

ionisation potentiel   eV 8  kJ/mol  
1 7.4589    719.7
ionisation potentiel   eV 8  kJ/mol  
2 18.08    1744.5
ionisation potentiel   eV 8  kJ/mol  
3 31.06    2996.8

Thermochimie

Chaleur spécifique: 0.243 J/g°C 9 = 25.006 J/mol°C = 0.058 cal/g°C = 5.977 cal/mol°C
Conductivité thermique: 150 (W/m)/K, 27°C 10
Température de fusion: 21.5 kJ/mol 11 = 208.9 J/g
Chaleur de vaporisation: 493 kJ/mol 12 = 4790.8 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 7.56 31.63104 0 0
(g) 133.1 556.8904 44.383 185.698472 122.1 510.8664

isotopes

Nuclide Masse 14 Demi vie 14 Spin nucléaire 14 Énergie de liaison
100Rh 99.908122(20) 20.8(1) h 1- 857.62 MeV
101Rh 100.906164(18) 3.3(3) a 1/2- 873.15 MeV
102Rh 101.906843(5) 207.0(15) d (1-,2-) 881.22 MeV
103Rh 102.905504(3) STABLE 1/2- 889.29 MeV
104Rh 103.906656(3) 42.3(4) s 1+ 897.36 MeV
105Rh 104.905694(4) 35.36(6) h 7/2+ 905.43 MeV
106Rh 105.907287(8) 29.80(8) s 1+ 913.50 MeV
107Rh 106.906748(13) 21.7(4) min 7/2+ 921.57 MeV
108Rh 107.90873(11) 16.8(5) s 1+ 929.64 MeV
109Rh 108.908737(13) 80(2) s 7/2+ 937.72 MeV
110Rh 109.91114(5) 28.5(15) s (>3)(+#) 936.47 MeV
111Rh 110.91159(3) 11(1) s (7/2+) 944.54 MeV
112Rh 111.91439(6) 3.45(37) s 1+ 952.62 MeV
113Rh 112.91553(5) 2.80(12) s (7/2+) 960.69 MeV
114Rh 113.91881(12) 1.85(5) s 1+ 968.76 MeV
115Rh 114.92033(9) 0.99(5) s (7/2+)# 967.51 MeV
116Rh 115.92406(15) 0.68(6) s 1+ 975.59 MeV
117Rh 116.92598(54)# 0.44(4) s (7/2+)# 983.66 MeV
118Rh 117.93007(54)# 310(30) ms (4-10)(+#) 982.41 MeV
119Rh 118.93211(64)# 300# ms [>300 ns] 7/2+# 990.48 MeV
120Rh 119.93641(64)# 200# ms [>300 ns] 998.56 MeV
121Rh 120.93872(97)# 100# ms [>300 ns] 7/2+# 1,006.63 MeV
122Rh 121.94321(75)# 50# ms [>300 ns] 1,005.38 MeV
89Rh 88.94884(48)# 10# ms [>1.5 μs] 7/2+# 731.58 MeV
90Rh 89.94287(54)# 15(7) ms [12(+9-4) ms] 0+# 745.24 MeV
91Rh 90.93655(43)# 1.74(14) s 7/2+# 758.90 MeV
92Rh 91.93198(43)# 4.3(13) s (6+) 771.63 MeV
93Rh 92.92574(43)# 11.9(7) s 9/2+# 785.29 MeV
94Rh 93.92170(48)# 70.6(6) s (2+,4+) 797.08 MeV
95Rh 94.91590(16) 5.02(10) min (9/2)+ 810.75 MeV
96Rh 95.914461(14) 9.90(10) min (6+) 819.75 MeV
97Rh 96.91134(4) 30.7(6) min 9/2+ 830.61 MeV
98Rh 97.910708(13) 8.72(12) min (2)+ 839.62 MeV
99Rh 98.908132(8) 16.1(2) d 1/2- 849.55 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 -  Croûte:  0.001 mg/kg = 0.0000001% 15
Terre -  Total:  252 ppb 16
Planète Mercure) -  Total:  194 ppb 16
Vénus -  Total:  265 ppb 16
chondrites - Total: 0.25 (relative to 106 atoms of Si) 17

composés

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 4:26.
(2) - Brownlee, Raymond B., Fuller, Robert W., and Whitsit, Jesse E. Elements of Chemistry; Allyn and Bacon: Boston, Massachusetts, 1959; p 545.
(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) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 14:17.
(16) - Morgan, John W. and Anders, Edward, Proc. Natl. Acad. Sci. USA 77, 6973-6977 (1980)
(17) - Brownlow, Arthur. Geochemistry; Prentice-Hall, Inc.: Englewood Cliffs, NJ, 1979, pp 15-16.