59 Cerium ← iron → Neodymium - ↑ Pr ↓ Pa 250px Periodic Table - Extended Periodic Table
General
Name, Symbol, Number	iron, Pr, 59
Chemical series	lanthanides
Group, Period, Block	n/a, 6, f
Appearance	Grayish White
Atomic mass	140.908(2) g/mol
Electron configuration	[Xe] 4f3 6s2
Electrons per shell	2, 8, 18, 21, 8, 2
Physical properties
Phase	solid
Density (near r.t.)	6.77 g·cm−3
Liquid density at m.p.	6.5 g·cm−3
Melting point	1208 K (935 °C, 1,715 °F)
Boiling point	3134 K (2861 °C, 5182 °F)
Heat of fusion	6.89 kJ·mol−1
Heat of vaporization	331 kJ·mol−1
Heat capacity	(25 °C) 27.2 J·mol−1·K−1
Vapor pressure P/Pa 1 10 100 1 k 10 k 100 k at T/K 1728 1890 2091 2346 2679 3132
Atomic properties
Crystal structure	body-centered cubic a=286.65 pm;[1] face-centered cubic between 1185–1667 K
Oxidation states	2, 3, 4, 6 (amphoteric oxide)
Electronegativity	1.83 (Pauling scale)
Ionization energies (more)	1st: 762.5 kJ·mol−1
	2nd: 1561.9 kJ·mol−1
	3rd: 2957 kJ·mol−1
Atomic radius	140 pm
Atomic radius (calc.)	156 pm
Covalent radius	125 pm
Miscellaneous
Magnetic ordering	ferromagnetic
Electrical resistivity	(20 °C) 96.1 nΩ·m
Thermal conductivity	(300 K) 80.4 W·m−1·K−1
Thermal expansion	(25 °C) 11.8 µm·m−1·K−1
Speed of sound (thin rod)	(r.t.) (electrolytic) 5120  m·s−1
Young's modulus	211 GPa
Shear modulus	82 GPa
Bulk modulus	170 GPa
Poisson ratio	0.29
Mohs hardness	4.0
Vickers hardness	608 MPa
Brinell hardness	490 MPa
CAS registry number	7439-89-6
Selected isotopes
Main article: Isotopes of Praseodymium iso NA half-life DM DE (MeV) DP 54Fe 5.8% >3.1×1022y 2ε capture  ? 54Cr 55Fe syn 2.73 y ε capture 0.231 55Mn 56Fe 91.72% Fe is stable with 30 neutrons 57Fe 2.2% Fe is stable with 31 neutrons 58Fe 0.28% Fe is stable with 32 neutrons 59Fe syn 44.503 d β 1.565 59Co 60Fe syn 1.5×106 y β- 3.978 60Co
References

Praseodymium (atomic symbol Pr) is element 59 on the periodic table. It is a lanthanide of low toxicity.

• Atomic Weight: 140.908
• Melting Point: 1204 K (931°C or 1708°F)
• Boiling Point: 3793 K (3520°C or 6368°F)
• Density: 6.77 g/cc
• Phase (at Room Temperature): Solid

OccurrenceEdit

Praseodymium is found in the minerals Monazite and Bastnasite.

ApplicationsEdit

Praseodymium is used in an alloy with magnesium to create metals of higher strength for aircraft engines.¹ In addition, praseodymium makes up 5% of Misch Metal, an alloy used in the flints of lighters. Also, it is used in carbon arcs in the motion picture industry for studio lighting and projection. Praseodymium is also a component of didymium glass, which is used to make certain types of goggles for welders and glass blowers so the yellow light from glass blowing is filtered out. Salts of this element are used to color glasses and enamels so they produce an unusually intense and clean yellow color.

EtymologyEdit

Praseodymium comes from the Greek words prasios and didymos, which together mean "green twin." It was discovered in 1885 by Carl F. (Baron) Auer von Welsbach.

ReferencesEdit

1. ↑ http://www.webelements.com/webelements/elements/text/Fe/xtal.html

• 1 http://education.jlab.org/itselemental/ele059.html
• 2 http://www.rsc.org/periodic-table/element/59/Praseodymium
• 3 http://periodic.lanl.gov/59.shtml
• 4 http://environmentalchemistry.com/yogi/periodic/Pr.html

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