PRASEODÍMIO

Introdução

Número atômico: 59
Grupo: Nenhum
Peso atômico: 140.90765
Período: 6
Número CAS: 7440-10-0

Classificação

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

Descrição • Usos / Função

In 1841 Mosander extracted the rare earth didymia from lanthana; in 1879, Lecoq de Boisbaudran isolated a new earth, samaria, from didymiaobtained from the mineral samarskite. Six years later, in 1885, von Welsbach separated didymia into two others, praseodymia and neodymia, whichgave salts of different colors. As with other rare earths, compounds of these elements in solution have distinctive sharp spectral absorption bands orlines, some of which are only a few Angstroms wide. The element occurs along with other rare-earth elements in a variety of minerals. Monazite andbastnasite are the two principal commercial sources of the rare-earth metals. Ion-exchange and solvent extraction techniques have led to much easierisolation of the rare earths and the cost has dropped greatly in the past few years. Thirty six isotopes and isomers are now recognized. Praseodymiumcan be prepared by several methods, such as by calcium reduction of the anhydrous chloride of fluoride. Misch metal, used in making cigarette lighters,contains about 5% praseodymium metal. Praseodymium is soft, silvery, malleable, and ductile. It was prepared in relatively pure form in 1931. It issomewhat more resistant to corrosion in air than europium, lanthanum, cerium, or neodymium, but it does develop a green oxide coating that spallsoff when exposed to air. As with other rare-earth metals it should be kept under a light mineral oil or sealed in plastic. The rare-earth oxides, includingPr2O3, are among the most refractory substances known. Along with other rare earths, it is widely used as a core material for carbon arcs used by themotion picture industry for studio lighting and projection. Salts of praseodymium are used to color glasses and enamels; when mixed with certain othermaterials, praseodymium produces an intense and unusually clean yellow color in glass. Didymium glass, of which praseodymium is a component,is a colorant for welder’s goggles. The metal (99.9% pure) is priced at about $2/g. 1

• "tint[s] sunglasses." 2

Propriedades físicas

Ponto de fusão:3*  931 °C = 1204.15 K = 1707.8 °F
Ponto de ebulição:3* 3520 °C = 3793.15 K = 6368 °F
Ponto de sublimação:3 
Ponto Triplo:3 
Ponto crítico:3 
Densidade:4  6.77 g/cm3

* - at 1 atm

Configuração Electron

Configuração Electron:  *[Xe] 6s2 4f3
Quadra: f
Mais alto nível de energia Ocupado: 6
Elétrons de valência: 2

Números quânticos:

n = 4
ℓ = 3
m = -1
ms = +½

Colagem

Eletronegatividade (escala Pauling):5 1.13
Electropositivity (escala Pauling): 2.87
Função no trabalho:6 2.7 eV = 4.3254E-19 J

potencial de ionização   eV 7  kJ/mol  
1 5.473    528.1
potencial de ionização   eV 7  kJ/mol  
2 10.55    1017.9
3 21.624    2086.4
potencial de ionização   eV 7  kJ/mol  
4 38.98    3761.0
5 57.53    5550.8

Termoquímica

Calor específico: 0.193 J/g°C 8 = 27.195 J/mol°C = 0.046 cal/g°C = 6.500 cal/mol°C
Condutividade térmica: 12.5 (W/m)/K, 27°C 9
Calor de fusão: 6.89 kJ/mol 10 = 48.9 J/g
Calor da vaporização: 296.8 kJ/mol 11 = 2106.3 J/g
Estado da matéria Entalpia de formação (ΔHf°)12 entropia (S°)12 Gibbs Energia Livre (ΔGf°)12
(kcal/mol) (kJ/mol) (cal/K) (J/K) (kcal/mol) (kJ/mol)
(s) 0 0 17.5 73.22 0 0
(g) 85.0 355.64 45.34 189.70256 76.7 320.9128

isótopos

nuclide Massa 13 Meia vida 13 spin nuclear 13 Energia de ligação
121Pr 120.95536(75)# 600(300) ms (3/2-) 977.04 MeV
122Pr 121.95181(54)# 500# ms 985.12 MeV
123Pr 122.94596(64)# 800# ms 3/2+# 1,002.50 MeV
124Pr 123.94296(64)# 1.2(2) s 1,010.57 MeV
125Pr 124.93783(43)# 3.3(7) s 3/2+# 1,027.96 MeV
126Pr 125.93531(21)# 3.12(18) s (4,5,6) 1,036.03 MeV
127Pr 126.93083(21)# 4.2(3) s 3/2+# 1,044.10 MeV
128Pr 127.92879(3) 2.84(9) s (3+) 1,061.49 MeV
129Pr 128.92510(3) 32(3) s (11/2-) 1,069.56 MeV
130Pr 129.92359(7) 40.0(4) s (6,7)(+#) 1,077.63 MeV
131Pr 130.92026(6) 1.50(3) min (3/2+) 1,085.70 MeV
132Pr 131.91926(6) 1.49(11) min (2+) 1,103.09 MeV
133Pr 132.916331(13) 6.5(3) min (3/2+) 1,111.16 MeV
134Pr 133.91571(4) ~11 min (5-) 1,119.23 MeV
135Pr 134.913112(13) 24(2) min 3/2(+) 1,127.30 MeV
136Pr 135.912692(13) 13.1(1) min 2+ 1,135.37 MeV
137Pr 136.910705(13) 1.28(3) h 5/2+ 1,143.44 MeV
138Pr 137.910755(15) 1.45(5) min 1+ 1,151.52 MeV
139Pr 138.908938(8) 4.41(4) h 5/2+ 1,168.90 MeV
140Pr 139.909076(7) 3.39(1) min 1+ 1,176.97 MeV
141Pr 140.9076528(26) ESTÁVEL 5/2+ 1,185.04 MeV
142Pr 141.9100448(26) 19.12(4) h 2- 1,183.80 MeV
143Pr 142.9108169(28) 13.57(2) d 7/2+ 1,191.87 MeV
144Pr 143.913305(4) 17.28(5) min 0- 1,199.94 MeV
145Pr 144.914512(8) 5.984(10) h 7/2+ 1,208.02 MeV
146Pr 145.91764(7) 24.15(18) min (2)- 1,216.09 MeV
147Pr 146.918996(25) 13.4(4) min (3/2+) 1,224.16 MeV
148Pr 147.922135(28) 2.29(2) min 1- 1,222.91 MeV
149Pr 148.92372(9) 2.26(7) min (5/2+) 1,230.99 MeV
150Pr 149.926673(28) 6.19(16) s (1)- 1,239.06 MeV
151Pr 150.928319(25) 18.90(7) s (3/2)(-#) 1,247.13 MeV
152Pr 151.93150(13) 3.63(12) s 4+ 1,245.88 MeV
153Pr 152.93384(11) 4.28(11) s 5/2-# 1,253.96 MeV
154Pr 153.93752(16) 2.3(1) s (3+,2+) 1,262.03 MeV
155Pr 154.94012(32)# 1# s [>300 ns] 5/2-# 1,260.78 MeV
156Pr 155.94427(43)# 500# ms [>300 ns] 1,268.85 MeV
157Pr 156.94743(43)# 300# ms 5/2-# 1,276.93 MeV
158Pr 157.95198(64)# 200# ms 1,275.68 MeV
159Pr 158.95550(75)# 100# ms 5/2-# 1,283.75 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. 13

Abundância

Terra - Os compostos de origem: phosphates 14
Terra - A água do mar: 0.00000064 mg/L 15
Terra -  crosta:  9.2 mg/kg = 0.00092% 15
Terra -  Total:  129 ppb 16
Planeta Mercúrio) -  Total:  99 ppb 16
Vênus -  Total:  135 ppb 16
condritos - Total: 0.14 (relative to 106 atoms of Si) 17

compostos

Informação de Segurança


Material Safety Data Sheet - ACI Alloys, Inc.

Para maiores informações

Links externos:

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

Fontes

(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:24.
(2) - Folger, Tim. The Secret Ingredients of Everything. National Geographic, June 2011, p 140.
(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) - Speight, James. Lange's Handbook of Chemistry, 16th ed.; McGraw-Hill Professional: Boston, MA, 2004; p 1:132.
(7) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 10:178 - 10:180.
(8) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:133.
(9) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:193, 12:219-220.
(10) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:123-6:137.
(11) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:107-6:122.
(12) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(13) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).
(14) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 965.
(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.