LANTHANUM

Introduction

Atomic Number: 57
Group: 3 or III B
Atomic Weight: 138.9055
Period: 6
CAS Number: 7439-91-0

Classification

Chalcogen
Halogen
Noble Gas
Lanthanoid
Actinoid
Rare Earth Metal
Platinum Group Metal
Transuranium
No Stable Isotopes
Solid
Liquid
Gas
Solid (Predicted)

Description

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

Uses/Function

•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

Physical Properties

Melting Point:5*  918 °C = 1191.15 K = 1684.4 °F
Boiling Point:5* 3464 °C = 3737.15 K = 6267.2 °F
Sublimation Point:5 
Triple Point:5 
Critical Point:5 
Density:6  6.15 g/cm3

* - at 1 atm

Electron Configuration

Electron Configuration:  *[Xe] 6s2 4f1
Block: d
Highest Occupied Energy Level: 6
Valence Electrons: 2

Quantum Numbers:

n = 4
ℓ = 3
m = -3
ms = +½

Bonding

Electronegativity (Pauling scale):7 1.10
Electropositivity (Pauling scale): 2.9
Electron Affinity:8 0.47 eV
Oxidation States: +3
Work Function:9 3.40 eV = 5.4468E-19 J

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

Thermochemistry

Specific Heat: 0.195 J/g°C 11 = 27.087 J/mol°C = 0.047 cal/g°C = 6.474 cal/mol°C
Thermal Conductivity: 13.5 (W/m)/K, 27ºC 12
Heat of Fusion: 6.2 kJ/mol 13 = 44.6 J/g
Heat of Vaporization: 414 kJ/mol 14 = 2980.4 J/g
State of Matter Enthalpy of Formation (ΔHf°)15 Entropy (S°)15 Gibbs Free Energy (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

Nuclide Mass 16 Half-Life 16 Nuclear Spin 16 Binding Energy
117La 116.95007(43)# 23.5(26) ms (3/2+,3/2-) 927.83 MeV
118La 117.94673(32)# 200# ms 945.23 MeV
119La 118.94099(43)# 1# s 11/2-# 953.31 MeV
120La 119.93807(54)# 2.8(2) s 970.70 MeV
121La 120.93301(54)# 5.3(2) s 11/2-# 978.78 MeV
122La 121.93071(32)# 8.6(5) s 986.86 MeV
123La 122.92624(21)# 17(3) s 11/2-# 1,004.25 MeV
124La 123.92457(6) 29.21(17) s (7-,8-) 1,012.33 MeV
125La 124.920816(28) 64.8(12) s (11/2-) 1,020.41 MeV
126La 125.91951(10) 54(2) s (5)(+#) 1,037.81 MeV
127La 126.916375(28) 5.1(1) min (11/2-) 1,045.89 MeV
128La 127.91559(6) 5.18(14) min (5+) 1,053.96 MeV
129La 128.912693(22) 11.6(2) min 3/2+ 1,062.04 MeV
130La 129.912369(28) 8.7(1) min 3(+) 1,070.12 MeV
131La 130.91007(3) 59(2) min 3/2+ 1,078.20 MeV
132La 131.91010(4) 4.8(2) h 2- 1,086.28 MeV
133La 132.90822(3) 3.912(8) h 5/2+ 1,103.67 MeV
134La 133.908514(21) 6.45(16) min 1+ 1,111.75 MeV
135La 134.906977(11) 19.5(2) h 5/2+ 1,119.83 MeV
136La 135.90764(6) 9.87(3) min 1+ 1,127.91 MeV
137La 136.906494(14) 6(2)E+4 a 7/2+ 1,135.99 MeV
138La 137.907112(4) 1.02(1)E+11 a 5+ 1,144.07 MeV
139La 138.9063533(26) STABLE 7/2+ 1,152.15 MeV
140La 139.9094776(26) 1.6781(3) d 3- 1,160.22 MeV
141La 140.910962(5) 3.92(3) h (7/2+) 1,158.99 MeV
142La 141.914079(6) 91.1(5) min 2- 1,167.07 MeV
143La 142.916063(17) 14.2(1) min (7/2)+ 1,175.14 MeV
144La 143.91960(5) 40.8(4) s (3-) 1,183.22 MeV
145La 144.92165(10) 24.8(20) s (5/2+) 1,181.99 MeV
146La 145.92579(8) 6.27(10) s 2- 1,190.06 MeV
147La 146.92824(5) 4.015(8) s (5/2+) 1,198.14 MeV
148La 147.93223(6) 1.26(8) s (2-) 1,196.91 MeV
149La 148.93473(34)# 1.05(3) s 5/2+# 1,204.98 MeV
150La 149.93877(43)# 510(30) ms (3+) 1,213.06 MeV
151La 150.94172(43)# 300# ms [>300 ns] 5/2+# 1,211.82 MeV
152La 151.94625(43)# 200# ms [>300 ns] 1,219.90 MeV
153La 152.94962(64)# 150# ms [>300 ns] 5/2+# 1,227.98 MeV
154La 153.95450(64)# 100# ms 1,226.74 MeV
155La 154.95835(86)# 60# ms 5/2+# 1,234.82 MeV
Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses. 16

Abundance

Earth - Source Compounds: phosphates 17
Earth - Seawater: 0.0000034 mg/L 18
Earth -  Crust:  39 mg/kg = 0.0039% 18
Earth -  Total:  379 ppb 19
Mercury -  Total:  291 ppb 19
Venus -  Total:  397 ppb 19
Chondrites - Total: 0.39 (relative to 106 atoms of Si) 20

Compounds

Safety Information


Material Safety Data Sheet - ACI Alloys, Inc.

Languages

Afrikaans:   Lantaan
Albanian:   Lantan
Armenian:   Լանթան
Arabic:   لانثانوم
Aromanian:   Lantan
Basque:   Lantanoa
Bosnian:   Lantan
Breton:   Lantan
Bulgarian:   Лантан
Belarusian:   Лантан
Catalan :   Lantani
Chinese :   镧
Cornish :   Lanthanum
Croatian :   Lantan
Czech :   Lanthan
Danish:   Lanthan
Dutch:   Lanthaan
Esperanto:   Lantano
Estonian:   Lantaan
Faroese:   Lanthan
Finnish:   Lantaani
French:   Lanthane
Friulan: Lantani
Frisian:   Lanthaan
Galician:   Lantano
Georgian:   ლანთანი
German:   Lanthan
Greek:   Λανθανιο
Hebrew:   לנתן
Hungarian:   Lantán
Icelandic:   Lantan or Lanþan
Irish Gaelic:   Lantainam
Italian:   Lantanio
Japanese:   ランタン
Kashubian:   Lantón
Kazakh:   Лантан
Korean:   란탄, 란타넘
Latvian:   Lantans
Lithuanian:   Lantanas
Luxembourgish:   Lanthan
Macedonian:   Лантан
Malay:   Lanthanum
Maltese :   Lantanum
Manx Gaelic:   Lantanum
Moksha:   Лантан
Mongolian:   Лантан
Norwegian:   Lantan
Occitan:   Lantan
Ossetian:   Лантан
Polish:   Lantan
Portuguese:   Lantâno
Russian:   Лантан
Scottish Gaelic:   Lantanam
Serbian:   Лантан
Slovak:   Lantán
Spanish:   Lantano
Sudovian:   Lantanas
Swahili:   Lanthani
Swedish:   Lantan
Tajik:   Lantan
Thai:   แลนทานัม
Turkish:   Lantan
Ukranian:   Лантан
Uzbek:   Лантан
Vietnamese:   Lantan
Welsh:   Lanthanwm

For More Information

External Links:

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

Sources

(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.