ESCANDIO

Introducción

Número Atómico: 21
Grupo: 3 or III B
Peso Atómico: 44.95591
Periodo: 4
Número CAS: 7440-20-2

Clasificación

Anfígeno
Halógeno
Gases nobles
Lantánido
Actínido
Tierras Raras
Platino Metal Grupo
Transuránicos
No Isótopos Estables
Sólido
Líquido
Gas
Sólido (Predicción)

Descripción

On the basis of the Periodic System, Mendeleev predicted the existence of ekaboron, which would have an atomic weight between 40 of calcium and 48 oftitanium. The element was discovered by Nilson in 1878 in the minerals euxenite and gadolinite, which had not yet been found anywhere except inScandinavia. By processing 10 kg of euxenite and other residues of rare-earth minerals, Nilson was able to prepare about 2 g of scandium oxide ofhigh purity. Cleve later pointed out that Nilson’s scandium was identical with Mendeleev’s ekaboron. Scandium is apparently a much more abundantelement in the sun and certain stars than here on earth. It is about the 23rd most abundant element in the sun, compared to the 50th most abundant onearth. It is widely distributed on earth, occurring in very minute quantities in over 800 mineral species. The blue color of beryl (aquamarine variety)is said to be due to scandium. It occurs as a principal component in the rare mineral thortveitite, found in Scandinavia and Malagasy. It is also foundin the residues remaining after the extraction of tungsten from Zinnwald wolframite, and in wiikite and bazzite. Most scandium is presently beingrecovered from thortveitite or is extracted as a by-product from uranium mill tailings. Metallic scandium was first prepared in 1937 by Fischer, Brunger,and Grieneisen, who electrolyzed a eutectic melt of potassium, lithium, and scandium chlorides at 700 to 800°C. Tungsten wire and a pool of moltenzinc served as the electrodes in a graphite crucible. Pure scandium is now produced by reducing scandium fluoride with calcium metal. The productionof the first pound of 99% pure scandium metal was announced in 1960. Scandium is a silver-white metal which develops a slightly yellowish or pinkishcast upon exposure to air. It is relatively soft, and resembles yttrium and the rare-earth metals more than it resembles aluminum or titanium. It is a verylight metal and has a much higher melting point than aluminum, making it of interest to designers of spacecraft. Scandium is not attacked by a 1:1mixture of conc. HNO3 and 48% HF. Scandium reacts rapidly with many acids. Nineteen isotopes and isomers of scandium are recognized. The metalis expensive, costing about $120/g with a purity of about 99.9%. Scandium oxide costs about $40/g. About 20 kg of scandium (as Sc2O3) are now beingused yearly in the U.S. to produce high-intensity lights, and the radioactive isotope 46Sc is used as a tracing agent in refinery crackers for crude oil,etc. Scandium iodide added to mercury vapor lamps produces a highly efficient light source resembling sunlight, which is important for indoor or nighttimecolor TV. Little is yet known about the toxicity of scandium; therefore, it should be handled with care. 1

Usos/Funciones

•It is well documented that the East German secret police - the Ministry for State Security, or "Stasi" employed scandium 46 for surveillance of human subjects during the 1970s and 1980s. Scandium 46 decays by emission of a high energy electron that can be easily detected several yards (several meters) from the source, even if there is an intervening barrier such as a wall. Anyone having on his or her person a scandium 46 source could therefore be "seen" without seeing the observer. It is not a naturally occurring isotope, however, so people would not normally carry around 46Sc, and the Stasi went to great efforts to plant sources on their surveillance targets. The radioactive material was acquired from a German nuclear research center, and special liquid sprays were developed that could be applied to cash or to a person's clothing or injected into a ballpoint pen." 2
•For improving the strength of aluminum materials, there is no better single element to add than scandium. Scandium-aluminum alloys are strong mainly because grain size is reduced. Small grains embedded in a metal lattice inhibit the transfer of a disturbance (such as caused by a forceful blow) through the material. Dislocation of the lattice is impeded at grain boundaries, and vibration is dispersed better when very small grains are distributed throughout the material.

Sc-Al alloys also exhibit excellent thermal stability. This feature makes a high-strength aluminum alloy easier to weld. It also reduces recrystallization. Crystallization weakens any object by restoring a rigid lattice that can have a higher shear tendency, leading to loss of strength. This tends to occur in items like bicycle frames and baseball bats that are cold-worked in their manufacture. Using Sc-Al alloys can alleviate this problem.

Recent studies have shown that the addition of small amounts of zirconium to scandium-aluminum alloys can have a dramatic effect on strength and thermal stability." 3
•Scandium has relatively few uses. Some scandium, however, is added to aluminum and magnesium alloys to strengthen them. Theoretically, scandium could replace aluminum as a structural material. Scandium weighs the same as aluminum but has a much higher melting point. However, the much higher cost of scandium makes large-scale use of scandium economically prohibitive.

Mixed with molybdenum, scandium helps to inhibit the corrosion of zirconium. Scandium metal has been used as a filter for high-speed neutrons in nuclear reactors." 4
•...researchers at Northwestern University experimented with adding zirconium to a scandium-aluminum alloy. They discovered the unexpected spontaneous formation of scandium-rich grains coated in zirconium-rich shells. Extremely tiny in size (nanometer scale), these grains seem to be the reason that Al-Sc-Zr alloys exhibit unusually high strength and thermal stability.

Experiments show that adding zirconium to an Al-Sc alloy suddenly and intensely disorders the material, so that scandium and zirconium become distributed fairly evenly before they begin to form grains (or precipitants). Scandium has a higher diffusion coefficient than zirconium, possibly due to atomic size or mass differences. This means that the scandium finds it easier to move around, collide, and form grains early on, while the zirconium moves more slowly, latching on to the grains after they have already formed. The resulting shell of zirconium surrounding a bead of scandium acts as a protective coating that keeps the grain from growing as a result of collisions with other particles.

As reported in the June 2006 issues of Nature Materials, researcher Peter Voorhees states that insights from this study will allow scientists to "design other alloys that form core-shell nanoparticles and, as a result, create new alloys with greatly enhanced properties." 5

Magnitudes Físicas

Punto de Fusión:6*  1541 °C = 1814.15 K = 2805.8 °F
Punto de Ebullición:6* 2836 °C = 3109.15 K = 5136.8 °F
Punto de Sublimación:6 
Punto Triple:6 
Punto Crítico:6 
Densidad:7  2.99 g/cm3

* - at 1 atm

Configuración Electrónica

Configuración Electrónica: [Ar] 4s2 3d1
Bloque: d
Nivel Más Alto de Energía Ocupados: 4
Electrones de Valencia: 2

Números Cuánticos:

n = 3
ℓ = 2
m = -2
ms = +½

Enlace Químico

Electronegatividad (Escala de Pauling):8 1.36
Electropositivity (Escala de Pauling): 2.64
Afinidad Electrónica:9 0.188 eV
Estados de Oxidación: +3
Función de Trabajo:10 3.5 eV = 5.607E-19 J

Energía de Ionización   eV 11  kJ/mol  
1 6.5615    633.1
2 12.79967    1235.0
3 24.75666    2388.7
4 73.4894    7090.6
5 91.65    8842.9
6 110.68    10679.0
7 138    13315.0
Energía de Ionización   eV 11  kJ/mol  
7 138    13315.0
8 158.1    15254.3
9 180.03    17370.3
10 225.18    21726.6
11 249.798    24101.8
12 687.36    66320.1
13 756.7    73010.4
14 830.8    80160.0
Energía de Ionización   eV 11  kJ/mol  
15 927.5    89490.1
16 1009    97353.7
17 1094    105554.9
18 1213    117036.7
19 1287.97    124270.2
20 5674.8    547534.8
21 6033.712    582164.6

Termoquímica

Capacidad Calorífica: 0.568 J/g°C 12 = 25.535 J/mol°C = 0.136 cal/g°C = 6.103 cal/mol°C
Conductividad Térmica: 15.8 (W/m)/K, 27ºC 13
Entalpía de Fusión: 14.1 kJ/mol 14 = 313.6 J/g
Entalpía de Vaporización: 314.2 kJ/mol 15 = 6989.1 J/g
Estado de Agregación de la Materia Entalpía de Formación (ΔHf°)16 Entropía (S°)16 Energía Libre de Gibbs (ΔGf°)16
(kcal/mol) (kJ/mol) (cal/K) (J/K) (kcal/mol) (kJ/mol)
(s) 0 0 8.28 34.64352 0 0
(g) 90.3 377.8152 41.75 174.682 80.32 336.05888

Isótopos

Nucleido Masa 17 Periodo de Semidesintegración 17 Espín 17 Energía de enlace nuclear
36Sc 36.01492(54)# 254.23 MeV
37Sc 37.00305(32)# 7/2-# 272.55 MeV
38Sc 37.99470(32)# <300 ns (2-)# 289.02 MeV
39Sc 38.984790(26) <300 ns (7/2-)# 306.41 MeV
40Sc 39.977967(3) 182.3(7) ms 4- 321.01 MeV
41Sc 40.96925113(24) 596.3(17) ms 7/2- 336.54 MeV
42Sc 41.96551643(29) 681.3(7) ms 0+ 348.35 MeV
43Sc 42.9611507(20) 3.891(12) h 7/2- 360.15 MeV
44Sc 43.9594028(19) 3.97(4) h 2+ 370.10 MeV
45Sc 44.9559119(9) ESTABLE 7/2- 381.90 MeV
46Sc 45.9551719(9) 83.79(4) d 4+ 389.98 MeV
47Sc 46.9524075(22) 3.3492(6) d 7/2- 400.85 MeV
48Sc 47.952231(6) 43.67(9) h 6+ 408.93 MeV
49Sc 48.950024(4) 57.2(2) min 7/2- 418.87 MeV
50Sc 49.952188(17) 102.5(5) s 5+ 425.09 MeV
51Sc 50.953603(22) 12.4(1) s (7/2)- 432.24 MeV
52Sc 51.95668(21) 8.2(2) s 3(+) 437.52 MeV
53Sc 52.95961(32)# >3 s (7/2-)# 442.81 MeV
54Sc 53.96326(40) 260(30) ms 3+# 447.16 MeV
55Sc 54.96824(79) 0.115(15) s 7/2-# 450.58 MeV
56Sc 55.97287(75)# 35(5) ms (1+) 454.93 MeV
57Sc 56.97779(75)# 13(4) ms 7/2-# 458.35 MeV
58Sc 57.98371(86)# 12(5) ms (3+)# 460.84 MeV
59Sc 58.98922(97)# 10# ms 7/2-# 463.33 MeV
60Sc 59.99571(97)# 3# ms 3+# 465.82 MeV
Los valores marcados con # no se derivan exclusivamente de datos experimentales, pero al menos en parte, de las tendencias sistemáticas. Tiradas con argumentos de asignación débiles están encerrados entre paréntesis. 17

Abundancia

Tierra - Fuente Compuestos: oxides 18
Tierra - Agua de mar: 0.0000006 mg/L 19
Tierra -  Corteza:  22 mg/kg = 0.0022% 19
Tierra -  Total:  9.6 ppm 20
Mercurio -  Total:  7.4 ppm 20
Venus -  Total:  10.1 ppm 20
Condritas - Total: 29 (relative to 106 atoms of Si) 21

Compuestos

Información Sobre Seguridad


Ficha de Datos de Seguridad - ACI Alloys, Inc.

Idiomas

Afrikáans:   Skandium
Albanés:   Skandium
Armenio:   Սկանդիում
Árabe:   سكانديوم
Arumano:   Scandiumu
Euskera:   Eskandioa
Bosnio:   Skandij
Bretón:   Skandiom
Búlgaro:   Скандий
Bielorruso:   Скандый
Catalán:   Escandi
Chino:   钪
Córnico:   Scandyum
Croata:   Skandij
Checo:   Skandium
Danés:   Scandium
Neerlandés:   Scandium
Esperanto:   Skandio
Estonio:   Skandium
Feroés:   Skandium
Finés:   Skandium
Francés:   Scandium
Friulano: Scandi
Frisio:   Scandium
Gallego:   Escandio
Georgiano:   სკანდიუმი
Alemán:   Skandium
Griego:   Σκανdιο
Hebreo:   סקנדיום
Húngaro:   Szkandium
Islandés:   Skandín
Irlandés:   Scaindiam
Italiano:   Scandio
Japonés:   スカンジウム
Casubio:   Skónd
Kazajo:   Скандий
Coreano:   스칸듐
Letónico:   Skandijs
Lituano:   Skandis
Luxemburgués:   Skandium
Macedonio:   Скандиум
Malayo:   Skandium
Maltés:   Skandjum
Manés:   Scandjum
Moksha:   Сканди
Mongol:   Сканди
Noruego:   Scandium
Occitano:   Escandi
Osetio:   Скандий
Polaco:   Skand
Portugués:   Escândio
Ruso:   Скандий
Gaélico Escocés:   Scaindiam
Serbio:   Скандиjум
Eslovaco:   Skandium
Español:   Escandio
:   Skandijan
Suajili:   Skandi
Sueco:   Skandium
Tayiko:   Skandi'
Tailandés:   สแคนเดียม
Turco:   Skandiyum
Ucraniano:   Скандій
Uzbeko:   Скандий
Vietnamita:   Scandi
Galés:   Scandiwm

Véase También

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 4:27.
(2) - Halka, Monica and Nordstrom, Brian. Transition Metals; Infobase Publishing: New York, NY, 2011; p 8.
(3) - Halka, Monica and Nordstrom, Brian. Transition Metals; Infobase Publishing: New York, NY, 2011; pp 9-10.
(4) - Halka, Monica and Nordstrom, Brian. Transition Metals; Infobase Publishing: New York, NY, 2011; p 10.
(5) - Halka, Monica and Nordstrom, Brian. Transition Metals; Infobase Publishing: New York, NY, 2011; pp 24-25.
(6) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:132.
(7) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 4:39-4:96.
(8) - Dean, John A. Lange's Handbook of Chemistry, 11th ed.; McGraw-Hill Book Company: New York, NY, 1973; p 4:8-4:149.
(9) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 10:147-10:148.
(10) - Speight, James. Lange's Handbook of Chemistry, 16th ed.; McGraw-Hill Professional: Boston, MA, 2004; p 1:132.
(11) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 10:178 - 10:180.
(12) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:133.
(13) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:193, 12:219-220.
(14) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:123-6:137.
(15) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:107-6:122.
(16) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(17) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).
(18) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 965.
(19) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 14:17.
(20) - Morgan, John W. and Anders, Edward, Proc. Natl. Acad. Sci. USA 77, 6973-6977 (1980)
(21) - Brownlow, Arthur. Geochemistry; Prentice-Hall, Inc.: Englewood Cliffs, NJ, 1979, pp 15-16.