Neodymium

Neodymium - Nd

CAS: 7440-00-8
Description:Silvery metal
Classification: Rare Earth (Lanthanide)
Date of Discovery: 1925
Discoverer: C.F. Aver von Welsbach
Name Origin: Greek neos, "new" and didymos, "twin"

Atomic Number: 60
Number of Neutrons: 84
Atomic Mass: 144.24 amu
Melting Point: 1010.0 °C
Boiling Point: 3127.0 °C
Density (293 K): 7.007 g/cm³
Atomic volume: 20.6 cm³/mol
Electrical resistivity: 0.0157 10^-6/cm

Thermal conductivity: 0.165 W/cmK
Enthalpy of atomization: 322 kJ/mol (est)
Enthalpy of vaporization: 273.0 kJ/mol
Enthalpy of fusion: 10.88 kJ/mol
Specific heat capacity: 0.19 J/gK

Energy levels: 2-8-18-22-8-2
Electron configuration: [Xe]4f ⁴6s²
Crystal Structure: Hexagonal
Atomic radius: 2.64 Å
Covalent radius: 1.64 Å
Oxidation States: +3
Electronegativity, Pauling: 1.14
Electron affinity:
First ionization energy: 5.53 eV
2nd ionization energy: 10.727 eV
3rd ionization energy: 22.076 eV
Polarizability: 31.4 10^-24cm³

Isotope	Natural Abundance	Atomic Mass	Half-life	Decay Mode	Spin
¹²⁷Nd	126.941	1.8 s	⁺, EC	(5/2)
¹²⁸Nd	127.935	4 s	⁺, EC
¹²⁹Nd	128.933	4.9 s	⁺, EC	5/2(-)
¹³⁰Nd	129.929	28 s	⁺, EC
¹³¹Nd	130.9271	0.5 m	⁺, EC
¹³²Nd	131.9231	1.5 m	⁺, EC
¹³³Nd	132.9222	1.2 m	⁺, EC
¹³⁴Nd	133.9187	8.5 m	⁺; EC	0+
^135mNd	5.5 m	⁺
¹³⁵Nd	134.9182	12 m	⁺; EC	9/2-
¹³⁶Nd	135.9150	50.6 m	EC; ⁺	0+
^137mNd	1.6 s	IT	11/2-
¹³⁷Nd	136.9146	38 m	⁺, EC	1/2+
¹³⁸Nd	137.9119	5.1 h	EC	0+
^139mNd	5.5 h	IT; ⁺	11/2-
¹³⁹Nd	138.91192	30 m	⁺; EC	3/2+
¹⁴⁰Nd	139.90931	3.37 d	EC	0+
^141mNd	1.04 m	EC; IT	11/2-
¹⁴¹Nd	140.909605	2.49 h	EC; ⁺	3/2+
¹⁴²Nd	27.13(12)	141.907719	Stable	0+
¹⁴³Nd	12.18(6)	142.909810	Stable	7/2-
¹⁴⁴Nd	23.80(12)	143.910083	2.1 x 10¹⁵ y	^-	0+
¹⁴⁵Nd	8.30(6)	144.912569	Stable	7/2-
¹⁴⁶Nd	17.19(9)	145.913113	Stable	0+
¹⁴⁷Nd	146.916096	10.98 d	^-	5/2-
¹⁴⁸Nd	5.76(3)	147.916889	Stable	0+
¹⁴⁹Nd	148.920145	1.73 h	^-	5/2-
¹⁵⁰Nd	5.64(3)	149.920887	Stable	0+
¹⁵¹Nd	150.923825	12.4 m	^-	(3/2+)
¹⁵²Nd	151.92468	11.4 m	^-	0+
¹⁵³Nd	152.9280	28.9 s	^-
¹⁵⁴Nd	153.9296	25.9 s	^-
¹⁵⁵Nd	154.9334	8.9 s	^-
¹⁵⁶Nd	155.9355	5.5 s	^-
In 1841, Mosander, extracted from cerite a new rose-colored oxide, which he believed contained a new element. He named the element didymium, as it was an inseparable twin brother of lanthanum. In 1885 von Welsbach separated didymium into two new elemental components, neodymia and praseodymia, by repeated fractionation of ammonium didymium nitrate. While the free metal is in misch metal, long known and used as a pyrophoric alloy for light flints, the element was not isolated in relatively pure form until 1925. Neodymium is present in misch metal to the extent of about 18%. It is present in the minerals monazite and bastnasite, which are principal sources of rare-earth metals. The element may be obtained by separating neodymium salts from other rare earths by ion-exchange or solvent extraction techniques, and by reducing anhydrous halides such as NdF₃ with calcium metal. Other separation techniques are possible. The metal has a bright silvery metallic luster. Neodymium is one of the more reactive rare-earth metals and quickly tarnishes in air, forming an oxide that spalls off and exposes metal to oxidation. The metal, therefore, should be kept under light mineral oil or sealed in a plastic material. Neodymium exists in two allotropic forms, with a transformation from a double hexagonal to a body-centered cubic structure taking place at 863 °C. Natural neodymium is a mixture of seven isotopes, one of which has a very long half-life. Twenty-seven other radioactive isotopes and isomers are recognized. Didymium, of which neodymium is a component, is used for coloring glass to make welder's goggles. By itself, neodymium colors glass delicate shades ranging from pure violet through wine-red and warm gray. Light transmitted through such glass shows unusually sharp absorption bands. The glass has been used in astronomical work to produce sharp bands by which spectral lines may be calibrated. Glass containing neodymium can be used as a laser material to produce coherent light. Neodymium salts are also used as a colorant for enamels. The element is also being used with iron and boron to produce extremely strong magnets having energy densities as high as 27 to 35 million gauss oersteds. These are the most compact magnets commercially available. Neodymium has a low-to-moderate acute toxic rating. As with other rare earths, neodymium should be handled with care. LINKS: Information, data sheet and standard forms The magnetic structures of neodymium How Magnetic Therapy Works to Relieve Pain Neodymium Magnet Products To Relieve Pain Neodymium Properties Return Sources for the information on this website include: Lide, David R., ed. CRC Handbook of Chemistry and Physics, 78th Ed., 1997-1998.

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