PRASEODIMIO

Introducción

Número atómico: 59
Grupo: Ninguna
Peso atomico: 140.90765
Período: 6
Número CAS: 7440-10-0

Clasificación

chalcogen
halógeno
Gas noble
Lantanoides
Actinoides
Elemento de tierras raras
Platino Metal Group
transuranium
No hay isótopos estables
Sólido
Líquido
Gas
Sólido (Predicho)

Descripción • Usos / Función

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

Propiedades físicas

Punto de fusion:3*  931 °C = 1204.15 K = 1707.8 °F
Punto de ebullición:3* 3520 °C = 3793.15 K = 6368 °F
Punto de sublimación:3 
Triple punto:3 
Punto crítico:3 
Densidad:4  6.77 g/cm3

* - at 1 atm

Configuración electronica

Configuración electronica:  *[Xe] 6s2 4f3
Bloquear: f
Ocupado más alto nivel de energía: 6
Electrones de valencia: 2

Números cuánticos:

n = 4
ℓ = 3
m = -1
ms = +½

Vinculación

electronegatividad (escala de Pauling):5 1.13
Electropositivity (escala de Pauling): 2.87
Función del trabajo:6 2.7 eV = 4.3254E-19 J

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

termoquímica

Calor especifico: 0.193 J/g°C 8 = 27.195 J/mol°C = 0.046 cal/g°C = 6.500 cal/mol°C
Conductividad térmica: 12.5 (W/m)/K, 27°C 9
Calor de fusión: 6.89 kJ/mol 10 = 48.9 J/g
Calor de vaporización: 296.8 kJ/mol 11 = 2106.3 J/g
Estado de la materia Entalpía de formación (ΔHf°)12 entropía (S°)12 Energía libre de Gibbs (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

nucleido Masa 13 Media vida 13 spin nuclear 13 Energía de unión
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) ESTABLE 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
Los valores marcados con # no son puramente derivan de los datos experimentales, pero al menos en parte, de las tendencias sistemáticas. Hace girar con débiles argumentos de asignación se incluyen entre paréntesis. 13

Abundancia

Tierra - Los compuestos de origen: phosphates 14
Tierra - Agua de mar: 0.00000064 mg/L 15
Tierra -  Corteza:  9.2 mg/kg = 0.00092% 15
Tierra -  Total:  129 ppb 16
Planeta mercurio) -  Total:  99 ppb 16
Venus -  Total:  135 ppb 16
condritas - Total: 0.14 (relative to 106 atoms of Si) 17

Compuestos

Información de seguridad


Ficha de datos de seguridad de materiales - ACI Alloys, Inc.

Para más información

Enlaces externos:

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

Fuentes

(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.