PROTACTINIO

Introducción

Número atómico: 91
Grupo: Ninguna
Peso atomico: 231.03588
Período: 7
Número CAS: 7440-13-3

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

The first isotope of element 91 to be discovered was protactinium-234, also known as UX2, a short-lived member of the naturally occurring uranium-238 decay series. It was identified by K. Fajans and O. H. Gohring in 1913 and they named the new element brevium. When the longer-lived isotope protactinium-231 was identified by Hahn and Meitner in 1918, the name protoactinium was adopted as being more consistent with the characteristics of the most abundant isotope. Soddy, Cranson, and Fleck were also active in this work. The name protoactinium was shortened to protactinium in 1949. In 1927, Grosse prepared 2 mg of a white powder, which was shown to be Pa2O5. Later, in 1934, from 0.1 g of pure Pa2O5 he isolated the element by two methods, one of which was by converting the oxide to an iodide and “cracking” it in a high vacuum by an electrically heated filament by the decomposition of protactinium (V) iodide to protactinium and iodine. Protactinium has a bright metallic luster which it retains for some time in air. The element occurs in pitchblende to the extent of about 1 part protactinium-231 to 10 million of ore. Ores from Zaire have about 3 ppm. Protactinium has twenty four isotopes and isomers, the most common of which is protactinium-231 with a half-life of 32,500 years. A number of protactinium compounds are known, some of which are colored. The element is superconductive below 1.4 K. The element is a dangerous toxic material and requires precautions similar to those used when handling plutonium. In 1959 and 1961, it was announced that the Great Britain Atomic Energy Authority extracted by a 12-stage process 125 g of 99.9% protactinium, the world’s only stock of the metal for many years to come. The extraction was made from 60 tons of waste material at a cost of about $500,000. Protactinium is one of the rarest and most expensive naturally occurring elements. 1

Propiedades físicas

Punto de fusion:2*  1572 °C = 1845.15 K = 2861.6 °F
Punto de ebullición:2
Punto de sublimación:2 
Triple punto:2 
Punto crítico:2 
Densidad:3  15.4 g/cm3

* - at 1 atm

Configuración electronica

Configuración electronica:  *[Rn] 7s2 5f3
Bloquear: f
Ocupado más alto nivel de energía: 7
Electrones de valencia: 2

Números cuánticos:

n = 5
ℓ = 3
m = -1
ms = +½

Vinculación

electronegatividad (escala de Pauling):4 1.5
Electropositivity (escala de Pauling): 2.5

potencial de ionización   eV 5  kJ/mol  
potencial de ionización   eV 5  kJ/mol  
potencial de ionización   eV 5  kJ/mol  
1 5.89    568.3

isótopos

nucleido Masa 6 Media vida 6 spin nuclear 6 Energía de unión
212Pa 212.02320(8) 8(5) ms [5.1(+61-19) ms] 7+# 1,621.29 MeV
213Pa 213.02111(8) 7(3) ms [5.3(+40-16) ms] 9/2-# 1,629.36 MeV
214Pa 214.02092(8) 17(3) ms 1,637.44 MeV
215Pa 215.01919(9) 14(2) ms 9/2-# 1,654.82 MeV
216Pa 216.01911(8) 105(12) ms 1,662.89 MeV
217Pa 217.01832(6) 3.48(9) ms 9/2-# 1,670.96 MeV
218Pa 218.020042(26) 0.113(1) ms 1,669.72 MeV
219Pa 219.01988(6) 53(10) ns 9/2- 1,687.11 MeV
220Pa 220.02188(6) 780(160) ns 1-# 1,685.86 MeV
221Pa 221.02188(6) 4.9(8) μs 9/2- 1,693.94 MeV
222Pa 222.02374(8)# 3.2(3) ms 1,702.01 MeV
223Pa 223.02396(8) 5.1(6) ms 1,710.08 MeV
224Pa 224.025626(17) 844(19) ms 5-# 1,718.15 MeV
225Pa 225.02613(8) 1.7(2) s 5/2-# 1,726.22 MeV
226Pa 226.027948(12) 1.8(2) min 1,734.29 MeV
227Pa 227.028805(8) 38.3(3) min (5/2-) 1,742.36 MeV
228Pa 228.031051(5) 22(1) h 3+ 1,741.12 MeV
229Pa 229.0320968(30) 1.50(5) d (5/2+) 1,749.19 MeV
230Pa 230.034541(4) 17.4(5) d (2-) 1,757.26 MeV
231Pa 231.0358840(24) 3.276(11)E+4 a 3/2- 1,765.33 MeV
232Pa 232.038592(8) 1.31(2) d (2-) 1,773.40 MeV
233Pa 233.0402473(23) 26.975(13) d 3/2- 1,772.16 MeV
234Pa 234.043308(5) 6.70(5) h 4+ 1,780.23 MeV
235Pa 235.04544(5) 24.44(11) min (3/2-) 1,788.30 MeV
236Pa 236.04868(21) 9.1(1) min 1(-) 1,796.37 MeV
237Pa 237.05115(11) 8.7(2) min (1/2+) 1,795.13 MeV
238Pa 238.05450(6) 2.27(9) min (3-)# 1,803.20 MeV
239Pa 239.05726(21)# 1.8(5) h (3/2)(-#) 1,811.27 MeV
240Pa 240.06098(32)# 2# min 1,810.03 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. 6

Abundancia

Tierra - Agua de mar: 0.00000000005 mg/L 7
Tierra -  Corteza:  0.0000014 mg/kg = 0.00000000014% 7

Compuestos

Información de seguridad


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

Para más información

Enlaces externos:

Fuentes

(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:25.
(2) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:132.
(3) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 4:39-4:96.
(4) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 10:178 - 10:180.
(5) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:193, 12:219-220.
(6) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:123-6:137.
(7) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:107-6:122.
(8) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).
(9) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 14:17.