RÓDIO

Introdução

Número atômico: 45
Grupo: 9 or VIII B
Peso atômico: 102.9055
Período: 5
Número CAS: 7440-16-6

Classificação

Calcogênio
halogênio
Gás nobre
Lantanóides
Actinóide
Terra-rara
Platinum Metal Group
Transuranium
Não Isótopos Estáveis
Sólido
Líquido
Gás
Sólido (previsto)

Descrição • Usos / Função

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

Propriedades físicas

Ponto de fusão:3*  1964 °C = 2237.15 K = 3567.2 °F
Ponto de ebulição:3* 3695 °C = 3968.15 K = 6683 °F
Ponto de sublimação:3 
Ponto Triplo:3 
Ponto crítico:3 
Densidade:4  12.4 g/cm3

* - at 1 atm

Configuração Electron

Configuração Electron:  *[Kr] 5s1 4d8
Quadra: d
Mais alto nível de energia Ocupado: 5
Elétrons de valência: 

Números quânticos:

n = 4
ℓ = 2
m = 0
ms = -½

Colagem

Eletronegatividade (escala Pauling):5 2.28
Electropositivity (escala Pauling): 1.72
Electron Affinity:6 1.137 eV
oxidação Unidos: +3,4,6
Função no trabalho:7 4.98 eV = 7.97796E-19 J

potencial de ionização   eV 8  kJ/mol  
1 7.4589    719.7
potencial de ionização   eV 8  kJ/mol  
2 18.08    1744.5
potencial de ionização   eV 8  kJ/mol  
3 31.06    2996.8

Termoquímica

Calor específico: 0.243 J/g°C 9 = 25.006 J/mol°C = 0.058 cal/g°C = 5.977 cal/mol°C
Condutividade térmica: 150 (W/m)/K, 27°C 10
Calor de fusão: 21.5 kJ/mol 11 = 208.9 J/g
Calor da vaporização: 493 kJ/mol 12 = 4790.8 J/g
Estado da matéria Entalpia de formação (ΔHf°)13 entropia (S°)13 Gibbs Energia Livre (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

isótopos

nuclide Massa 14 Meia vida 14 spin nuclear 14 Energia de ligação
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) ESTÁVEL 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
Os valores marcados # não são puramente derivado a partir de dados experimentais, mas, pelo menos, parcialmente a partir de tendências sistemáticas. Gira com argumentos de atribuição fracos estão entre parênteses. 14

Abundância

Terra -  crosta:  0.001 mg/kg = 0.0000001% 15
Terra -  Total:  252 ppb 16
Planeta Mercúrio) -  Total:  194 ppb 16
Vênus -  Total:  265 ppb 16
condritos - Total: 0.25 (relative to 106 atoms of Si) 17

compostos

Informação de Segurança


Material Safety Data Sheet - ACI Alloys, Inc.

Para maiores informações

Links externos:

Fontes

(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.