LANTHAN

Einführung

Ordnungszahl: 57
Gruppe: 3 or III B
Atomares Gewicht: 138.9055
Periode: 6
CAS-Nummer: 7439-91-0

Einstufung

Metall
Nonmetal
metalloider
Alkalimetall
Erdalkalimetalls
Übergangsmetall
Chalkogenhaltige
Halogen
Edelgas
Lanthanoid
Actinoidenelemente
Seltene Erden
Platingruppenmetall
Transurane
Keine Stabile Isotope
Solide
Flüssigkeit
Gas
Solide (Prognostizierte)

Beschreibung • Verwendung / Funktion

Mosander in 1839 extracted a new earth lanthana, from impure cerium nitrate, and recognized the new element. Lanthanum is found in rare-earthminerals such as cerite, monazite, allanite, and bastnasite. Monazite and bastnasite are principal ores in which lanthanum occurs in percentages upto 25 and 38%, respectively. Misch metal, used in making lighter flints, contains about 25% lanthanum. Lanthanum was isolated in relatively pureform in 1923. Iron-exchange and solvent extraction techniques have led to much easier isolation of the so-called “rare-earth” elements. The availabilityof lanthanum and other rare earths has improved greatly in recent years. The metal can be produced by reducing the anhydrous fluoride with calcium.Lanthanum is silvery white, malleable, ductile, and soft enough to be cut with a knife. It is one of the most reactive of the rare-earth metals. It oxidizesrapidly when exposed to air. Cold water attacks lanthanum slowly, and hot water attacks it much more rapidly. The metal reacts directly with elementalcarbon, nitrogen, boron, selenium, silicon, phosphorus, sulfur, and with halogens. At 310°C, lanthanum changes from a hexagonal to a face-centeredcubic structure, and at 865°C it again transforms into a body-centered cubic structure. Natural lanthanum is mixture of two isotopes, one of which isstable and one of which is radioactive with a very long half-life. Twenty nine other radioactive isotopes are recognized. Rare-earth compoundscontaining lanthanum are extensively used in carbon lighting applications, especially by the motion picture industry for studio lighting and projection.This application consumes about 25% of the rare-earth compounds produced. La2O3 improves the alkali resistance of glass, and is used in makingspecial optical glasses. Small amounts of lanthanum, as an additive, can be used to produce nodular cast iron. There is current interest in hydrogensponge alloys containing lanthanum. These alloys take up to 400 times their own volume of hydrogen gas, and the process is reversible. Heat energyis released every time they do so; therefore these alloys have possibilities in energy conservation systems. Lanthanum and its compounds have a lowto moderate acute toxicity rating; therefore, care should be taken in handling them. The metal costs about $2/g (99.9%). 1

• "The battery in a single Toyota Prius contains more than 20 pounds of the rare earth element lanthanum" 2
• "Night-vision goggles require lanthanum" 3
• "catalyst in refining oil to gasoline" 4

Physikalische Eigenschaften

Schmelzpunkt:5*  918 °C = 1191.15 K = 1684.4 °F
Siedepunkt:5* 3464 °C = 3737.15 K = 6267.2 °F
Sublimationspunkt:5 
Dreifacher Punkt:5 
Kritischer Punkt:5 
Dichte:6  6.15 g/cm3

* - at 1 atm

Elektronenkonfiguration

Elektronenkonfiguration:  *[Xe] 6s2 4f1
Block: d
Höchster besetztes Energieniveau: 6
Valenzelektronen: 

Quantenzahlen:

n = 4
ℓ = 3
m = -3
ms = +½

Kleben

Elektronegativität (Pauling-Skala):7 1.10
Electropositivity (Pauling-Skala): 2.9
Elektronenaffinität:8 0.47 eV
oxidations~~POS=TRUNC: +3
Arbeitsfuntkion:9 3.40 eV = 5.4468E-19 J

Ionisationspotential   eV 10  kJ/mol  
1 5.5769    538.1
Ionisationspotential   eV 10  kJ/mol  
2 11.06    1067.1
3 19.1773    1850.3
Ionisationspotential   eV 10  kJ/mol  
4 49.95    4819.4
5 61.6    5943.5

Thermochemie

Spezifische Wärme: 0.195 J/g°C 11 = 27.087 J/mol°C = 0.047 cal/g°C = 6.474 cal/mol°C
Wärmeleitfähigkeit: 13.5 (W/m)/K, 27°C 12
Schmelzwärme: 6.2 kJ/mol 13 = 44.6 J/g
Verdampfungswärme: 414 kJ/mol 14 = 2980.4 J/g
Aggregatszustand Bildungsenthalpie (ΔHf°)15 Entropie (S°)15 Gibbs-Energie (ΔGf°)15
(kcal/mol) (kJ/mol) (cal/K) (J/K) (kcal/mol) (kJ/mol)
(s) 0 0 13.6 56.9024 0 0
(g) 103.0 430.952 43.56 182.25504 94.07 393.58888

Isotopes

Nuklid Masse 16 Halbwertzeit 16 Kernspin 16 Bindungsenergie
117La 116.95007(43)# 23.5(26) ms (3/2+,3/2-) 946.32 MeV
118La 117.94673(32)# 200# ms 963.71 MeV
119La 118.94099(43)# 1# s 11/2-# 971.78 MeV
120La 119.93807(54)# 2.8(2) s 989.17 MeV
121La 120.93301(54)# 5.3(2) s 11/2-# 997.24 MeV
122La 121.93071(32)# 8.6(5) s 1,005.31 MeV
123La 122.92624(21)# 17(3) s 11/2-# 1,022.70 MeV
124La 123.92457(6) 29.21(17) s (7-,8-) 1,030.77 MeV
125La 124.920816(28) 64.8(12) s (11/2-) 1,038.84 MeV
126La 125.91951(10) 54(2) s (5)(+#) 1,056.23 MeV
127La 126.916375(28) 5.1(1) min (11/2-) 1,064.30 MeV
128La 127.91559(6) 5.18(14) min (5+) 1,072.37 MeV
129La 128.912693(22) 11.6(2) min 3/2+ 1,080.44 MeV
130La 129.912369(28) 8.7(1) min 3(+) 1,088.51 MeV
131La 130.91007(3) 59(2) min 3/2+ 1,096.58 MeV
132La 131.91010(4) 4.8(2) h 2- 1,104.65 MeV
133La 132.90822(3) 3.912(8) h 5/2+ 1,122.04 MeV
134La 133.908514(21) 6.45(16) min 1+ 1,130.11 MeV
135La 134.906977(11) 19.5(2) h 5/2+ 1,138.18 MeV
136La 135.90764(6) 9.87(3) min 1+ 1,146.25 MeV
137La 136.906494(14) 6(2)E+4 a 7/2+ 1,154.32 MeV
138La 137.907112(4) 1.02(1)E+11 a 5+ 1,162.40 MeV
139La 138.9063533(26) STABIL 7/2+ 1,170.47 MeV
140La 139.9094776(26) 1.6781(3) d 3- 1,178.54 MeV
141La 140.910962(5) 3.92(3) h (7/2+) 1,177.29 MeV
142La 141.914079(6) 91.1(5) min 2- 1,185.37 MeV
143La 142.916063(17) 14.2(1) min (7/2)+ 1,193.44 MeV
144La 143.91960(5) 40.8(4) s (3-) 1,201.51 MeV
145La 144.92165(10) 24.8(20) s (5/2+) 1,200.27 MeV
146La 145.92579(8) 6.27(10) s 2- 1,208.34 MeV
147La 146.92824(5) 4.015(8) s (5/2+) 1,216.41 MeV
148La 147.93223(6) 1.26(8) s (2-) 1,215.16 MeV
149La 148.93473(34)# 1.05(3) s 5/2+# 1,223.24 MeV
150La 149.93877(43)# 510(30) ms (3+) 1,231.31 MeV
151La 150.94172(43)# 300# ms [>300 ns] 5/2+# 1,230.06 MeV
152La 151.94625(43)# 200# ms [>300 ns] 1,238.13 MeV
153La 152.94962(64)# 150# ms [>300 ns] 5/2+# 1,246.21 MeV
154La 153.95450(64)# 100# ms 1,244.96 MeV
155La 154.95835(86)# 60# ms 5/2+# 1,253.03 MeV
Werte markiert # sind nicht rein aus experimentellen Daten abgeleitet, aber zumindest teilweise von der systematischen Trends. Dreht mit schwachen Zuordnung Argumente in Klammern eingeschlossen sind. 16

Die Reaktionen

Fülle

Erde - Ausgangsverbindungen: phosphates 17
Erde - Meerwasser: 0.0000034 mg/L 18
Erde -  Kruste:  39 mg/kg = 0.0039% 18
Erde -  Gesamt:  379 ppb 19
Der Planet Merkur) -  Gesamt:  291 ppb 19
Venus -  Gesamt:  397 ppb 19
Chondrite - Gesamt: 0.39 (relative to 106 atoms of Si) 20

Verbindungen

Sicherheitsinformation


Datenblatt zur Materialsicherheit - ACI Alloys, Inc.

Für mehr Informationen

Externe Links:

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

Quellen

(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:17.
(2) - Folger, Tim. The Secret Ingredients of Everything. National Geographic, June 2011, p 138.
(3) - Folger, Tim. The Secret Ingredients of Everything. National Geographic, June 2011, p 140.
(4) - Folger, Tim. The Secret Ingredients of Everything. National Geographic, June 2011, p 143.
(5) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:132.
(6) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 4:39-4:96.
(7) - Dean, John A. Lange's Handbook of Chemistry, 11th ed.; McGraw-Hill Book Company: New York, NY, 1973; p 4:8-4:149.
(8) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 10:147-10:148.
(9) - Speight, James. Lange's Handbook of Chemistry, 16th ed.; McGraw-Hill Professional: Boston, MA, 2004; p 1:132.
(10) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 10:178 - 10:180.
(11) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:133.
(12) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:193, 12:219-220.
(13) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:123-6:137.
(14) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:107-6:122.
(15) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(16) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).
(17) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 965.
(18) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 14:17.
(19) - Morgan, John W. and Anders, Edward, Proc. Natl. Acad. Sci. USA 77, 6973-6977 (1980)
(20) - Brownlow, Arthur. Geochemistry; Prentice-Hall, Inc.: Englewood Cliffs, NJ, 1979, pp 15-16.