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PRASEODYMIUM
Links:
Introduction Classification Description Physical Properties
Electron Configuration and Bonding Thermochemistry Video
Isotopes Reactions Abundance Compounds
Safety Languages For More Information Sources
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Introduction

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Atomic Number: 59 Group: None 59 140.90765
Average Atomic Mass: 140.90765 Period: 6

Pr
   

CAS Number:

 7440-10-0
      Praseodymium
Classification

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Metal Nonmetal Metalloid    
Alkali Metal Alkali Earth Metal Transition Metal Chalcogen Halogen
Noble Gas Lanthanoid Actinoid

Rare Earth Metal

  
Transuranium No Stable Isotopes      
Solid Liquid Gas

Assumed Solid

  
Description

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In 1841 Mosander extracted the rare earth didymia from lanthana; in 1879, Lecoq de Boisbaudran isolated a new earth, samaria, from didymia obtained from the mineral samarskite. Six years later, in 1885, von Welsbach separated didymia into two others, praseodymia and neodymia, which gave salts of different colors. As with other rare earths, compounds of these elements in solution have distinctive sharp spectral absorption bands or lines, some of which are only a few Angstroms wide. The element occurs along with other rare-earth elements in a variety of minerals. Monazite and bastnasite are the two principal commercial sources of the rare-earth metals. Ion-exchange and solvent extraction techniques have led to much easier isolation of the rare earths and the cost has dropped greatly in the past few years. Thirty six isotopes and isomers are now recognized. Praseodymium can 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 is somewhat more resistant to corrosion in air than europium, lanthanum, cerium, or neodymium, but it does develop a green oxide coating that spalls off 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, including Pr2O3, 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 the motion picture industry for studio lighting and projection. Salts of praseodymium are used to color glasses and enamels; when mixed with certain other materials, 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
Physical Properties

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Normal Melting Point: 931 °C = 1204.15 K = 1707.8 °F 2 Normal Boiling Point: 3520 °C = 3793.15 K = 6368 °F 2
Sublimation Point: Triple Point:
Critical Point:
Density: 6.77 g/cm3 Crystal Structure: hexagonal
Atomic Radius: 2.67 Ǻ = 267 pm Covalent Radius: 1.65 Ǻ = 165 pm
Ionic Radius: 1 Ǻ = 100 pm Atomic Volume: 20.8 cm3/mol
Qualitative Solubility: s hot H2O, acid 3
Note: Unless otherwise stated, solubility is for water at 25 degrees Celsius.
Electron Configuration and Bonding

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Predicted Electron Configuration: [Xe] 6s2 5d1 4f2

Lewis Dot Diagram
Actual Electron Configuration: [Xe] 6s2 4f3  

x

 
Block: f

Pr

x
Highest Occupied Energy Level: 6

Valence Electrons: 2  

 
Quantum Numbers: n = 4 ℓ = 3 mℓ = -1 ms = +½        
Please note that information in this section can be derived entirely from the periodic table.  Although most people do not discuss valence electrons of the d-block and f-block elements, on this page the number of electrons in the highest energy level of the actual electron configuration was used to determine valence electrons.
Electronegativity (Pauling): 1.13 Electropositivity (Pauling): 2.87
Electron Affinity: Oxidation States: +3,4
Work Function:4 2.7 eV = 4.3254E-19 J  
Ionization Potential 5 eV kJ/mol Ionization Potential 5 eV kJ/mol
1 5.473 528.1 4 38.98 3761.0
2 10.55 1017.9 5 57.53 5550.8
3 21.624 2086.4
Note: Only the electronvolt values are given in the CRC Handbook, a conversion factor was used to find the kJ/mol value.
Thermochemistry

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Specific Heat: 0.19 J/g°C = 0.045 cal/g°C Thermal Conductivity: 12.5 (W/m)/K, 27ºC
Heat of Fusion: 6.89 kJ/mol = 48.9 J/g Heat of Vaporization: 296.8 kJ/mol = 2106.3 J/g
State of Matter Enthalpy of Formation Entropy of Formation Gibbs Free Energy
(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
Video

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Video on praseodymium from the University of Nottingham's periodicvideos.com
Isotopes

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Nuclide Mass Half-Life Nuclear Spin Binding Energy (kJ/mol)
121Pr 120.95536(75)# 600(300) ms (3/2-) 92415946547.0542
122Pr 121.95181(54)# 500# ms 93195357492.3218
123Pr 122.94596(64)# 800# ms 3/2+# 94873580809.609
124Pr 123.94296(64)# 1.2(2) s 95652991754.8779
125Pr 124.93783(43)# 3.3(7) s 3/2+# 97331215072.1626
126Pr 125.93531(21)# 3.12(18) s (4,5,6) 98110626017.4314
127Pr 126.93083(21)# 4.2(3) s 3/2+# 98890036962.7003
128Pr 127.92879(3) 2.84(9) s (3+) 100568260279.989
129Pr 128.92510(3) 32(3) s (11/2-) 101347671225.258
130Pr 129.92359(7) 40.0(4) s (6,7)(+#) 102127082170.524
131Pr 130.92026(6) 1.50(3) min (3/2+) 102906493115.79
132Pr 131.91926(6) 1.49(11) min (2+) 104584716433.079
133Pr 132.916331(13) 6.5(3) min (3/2+) 105364127378.345
134Pr 133.91571(4) ~11 min (5-) 106143538323.614
135Pr 134.913112(13) 24(2) min 3/2(+) 106922949268.88
136Pr 135.912692(13) 13.1(1) min 2+ 107702360214.147
137Pr 136.910705(13) 1.28(3) h 5/2+ 108481771159.415
138Pr 137.910755(15) 1.45(5) min 1+ 109261182104.682
139Pr 138.908938(8) 4.41(4) h 5/2+ 110939405421.97
140Pr 139.909076(7) 3.39(1) min 1+ 111718816367.237
141Pr 140.9076528(26) STABLE 5/2+ 112498227312.503
142Pr 141.9100448(26) 19.12(4) h 2- 112378825885.752
143Pr 142.9108169(28) 13.57(2) d 7/2+ 113158236831.016
144Pr 143.913305(4) 17.28(5) min 0- 113937647776.285
145Pr 144.914512(8) 5.984(10) h 7/2+ 114717058721.551
146Pr 145.91764(7) 24.15(18) min (2)- 115496469666.82
147Pr 146.918996(25) 13.4(4) min (3/2+) 116275880612.087
148Pr 147.922135(28) 2.29(2) min 1- 116156479185.333
149Pr 148.92372(9) 2.26(7) min (5/2+) 116935890130.6
150Pr 149.926673(28) 6.19(16) s (1)- 117715301075.866
151Pr 150.928319(25) 18.90(7) s (3/2)(-#) 118494712021.135
152Pr 151.93150(13) 3.63(12) s 4+ 118375310594.379
153Pr 152.93384(11) 4.28(11) s 5/2-# 119154721539.646
154Pr 153.93752(16) 2.3(1) s (3+,2+) 119934132484.914
155Pr 154.94012(32)# 1# s [>300 ns] 5/2-# 119814731058.161
156Pr 155.94427(43)# 500# ms [>300 ns] 120594142003.428
157Pr 156.94743(43)# 300# ms 5/2-# 121373552948.696
158Pr 157.95198(64)# 200# ms 121254151521.941
159Pr 158.95550(75)# 100# ms 5/2-# 122033562467.21
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. 6
Reactions

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Abundance

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Earth: Source Compounds: phosphates 7
Earth: Ocean Water: 0.00000064 mg/L 8
Earth: Crust: 9.2 mg/kg = 0.00092% 8
Earth: Total: 129 ppb 9
Mercury: Total: 99 ppb 9
Venus: Total: 135 ppb 9
Compounds

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praseodymium(II) fluoride praseodymium(III) chloride praseodymium(III) nitride
praseodymium(II) iodide praseodymium(III) fluoride praseodymium(III) oxide
praseodymium(II) selenide praseodymium(III) formate praseodymium(III) sulfide
praseodymium(II) sulfide praseodymium(III) iodide praseodymium(III) telluride
praseodymium(II) telluride praseodymium(III) nitrate hexahydrate praseodymium(IV) fluoride
praseodymium(III) bromide praseodymium(III) nitrate pentahydrate praseodymium(IV) oxide
Safety

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Note: Not every link below has an entry for every element on the periodic table.  Sites were selected based on those that had a large number of element and compound entries.
Scorecard's Pollution Information − not an MSDS, but it does provide basic information (among other things) on human heath hazards and industrial uses.
Although not truly an MSDS, Oxford University's Physical and Theoretical Chemistry Laboratory does provide some basic information.
Iowa State University
ESPI Metals
Languages

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Afrikaans: Praseodimium Albanian: Prazeodim Armenian: Պրազեդիում Arabic: براسيوديميوم
Aromanian: Prazeoodimiumu Basque: Praseodimioa Bosnian: Praseodimij Breton: Prazeodim
Bulgarian: Празеодим Byelorussian: Празеадым Catalan: Praseodimi Chinese: 镨
Cornish: Prasodyum Croatian: Praseodimij Czech: Praseodym Danish: Praseodymium
Dutch: Praseodymium Esperanto: Prazeodimo Estonian: Praseodüüm Faroese: Praseodymium
Finnish: Praseodyymi French: Praséodyme Friulian: Praseodimi Frisian: Praseodymium
Galician: Praseodimio Georgian: პრაზეოდიმი German: Praseodym Greek: Πρασεοδυμιο
Hebrew: פרסיאודימיום Hungarian: Prazeodímium Icelandic: Praseódým Irish Gaelic: Praiséidimiam
Italian: Praseodimio Japanese: プラセオジム Kashubian: Prazeòdim Kazakh: Празеодий
Korean: 프라세오디뮴 Latvian: Praseodims Lithuanian: Prazeodimis Luxembourgish: Praseodym
Macedonian: Празеодимиум Malay: Praseodimium Maltese: Praseodimjum Manx Gaelic: Prashodymmium
Mokshan: Праседими Mongolian: Празеодим Norwegian: Praseodym Occitan: Praseodimi
Ossetian: Празеодий Polish: Prazeodym Portuguese: Praseodímio Russian: Празеодий
Scottish Gaelic: Praiseoidimiam Serbian: Празеодиjум Slovak: Prazeodým Spanish: Prosedimio
Sudovian: Prazeadimis Swahili: Praseodimi Swedish: Praseodym Tajik: Prazeodim
Thai: เพรซิโอดิเมียม Turkish: Praseodim Ukranian: Празеодим Uzbek: Празеодий
Vietnamese: Prazeodim Welsh: Praseodiwm        
For More Information

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From Online Periodic Tables:
About.com American Elements
Chemical & Engineering News Chemical Elements
ChemGlobe Chemicool
Environmental Chemistry Eni Generalic
HyperPhysics from Georgia State University's Department of Physics and Astronomy InfoPlease
Lenntech Los Alamos National Laboratory
Physics Department of the University of Coimbra Qivx Inc.
Royal Society of Chemistry's Visual Elements Schenectady County Community College
Thomas Jefferson Lab National Accelerator Facility WebElements
Wikipedia X-ray properties: Carlo Segre from Illinois Institute of Technology
Sources

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(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4-24.
(2) - Lide, David R. CRC Handbook; CRC Press: Boca Raton, FL, 2002; p 4-132.
(3) - Dean, John A. Lange's Handbook of Chemistry, 11th ed.; McGraw-Hill Book Company: New York, NY, 1973; p 4-8 - 4-149.
(4) - Speight, James. Lange's Handbook of Chemistry, 16th ed.; McGraw-Hill Professional: Boston, MA, 2004; p 1-132.
(5) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 10-178 - 10-180.
(6) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).
(7) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 965.
(8) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 14-17.
(9) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 962.

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Last update: Thursday, August 12, 2010