Neodymium Element Facts / Chemistry

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60 Nd 144.24 Neodymium

Name: Neodymium
Type: Rare Earth, Lanthanide series
Density @ 293 K: 7.0 g/cm³

Discovery of Neodymium
Neodymium was first identified in 1885 by Carl Auer von Welsbach. It was discovered in 'didymium,' a substance incorrectly identified by Carl Mosander as a new element in 1841. ⁽¹⁾

The nonexistent 'didymium' was even given the symbol Di in Mendeleev's first edition of the periodic table in 1869.

In 1879 Lecoq de Boisbaudran detected and separated samarium from 'didymium.' ^(1a)

After samarium had been discovered, it was noted that 'didymium's' absorption spectrum gave different results depending on which mineral it had been sourced from. ⁽²⁾

Bohuslav Brauner published a paper on atomic weight determinations in 1882 for rare earth elements and his data for 'didymium' were variable. Brauner became convinced that 'didymium' was a mixture of elements; he attempted to separate them, but he was not successful. ⁽²⁾

In 1885 Carl Welsbach, who had discovered 'didymium' 14 years earlier, realized it was actually a mixture of two entirely new elements. He named these neodymium and praseodymium. Welsbach reacted 'didymium' to form nitrate salts, which he then fractionally crystallized from nitric acid to yield pink neodymium and greenish-brown praseodymium salts.

The fractional crystallization experiments were very time consuming, involving more than one hundred crystallization operations, each lasting up to 48 hours.

Neodymium was named with 'neos didymos' - Greek for 'new twin,' reflecting neodymium's close association with praseodymium.

Pure neodymium metal was isolated in 1925 by H. Kremers.

Symbol: Nd
Atomic weight: 144.24
Atomic volume: 20.6 cm³/mol

State (s, l, g): solid
Melting point: 1289 K   (1016 ^oC)

Boiling point: 3343 K   (3070 ^oC)

Specific heat capacity: 0.19 J g^-1 K^-1
Heat of fusion: 7.140 kJ mol^-1
1^st ionization energy: 529.6 kJ mol^-1
3^rd ionization energy: 2130 kJ mol^-1

Heat of atomization: 328 kJ mol^-1
Heat of vaporization : 283.68 kJ mol^-1
2^nd ionization energy: 1035 kJ mol^-1
Electron affinity: 50 kJ mol^-1

Shells: 2,8,18,22,8,2
Minimum oxidation number: 0
Min. common oxidation no.: 0
Electronegativity (Pauling Scale): 1.14

Electron configuration: [Xe] 4f⁴ 6s²
Maximum oxidation number: 3
Max. common oxidation no.: 3
Polarizability volume: 31.4 ų

Structure: close packed (ABCB)
Hardness: mohs

Color: silvery-white


Harmful effects:
Neodymium is considered to be moderately toxic.

Characteristics:
Neodymium is a soft, bright, silvery white metal. It is one of the lanthanide rare earth metals. It forms a flaky oxide coating in air. Unlike many metal oxide layers, this one does not protect the metal from further oxidation.

Neodymium has two allotropic forms, transforming from hexagonal to body-centered cubic above 800K (527 ^oC).

Neodymium usually exists as a trivalent ion, Nd³⁺, in its compounds. Most of its salts are pale purple in color.

Uses:
Neodymium is used with iron and boron to create powerful permanent magnets, also called NIB magnets. NIB magnets are used in computers, cell phones, medical equipment, toys, motors, wind turbines and audio systems. ⁽³⁾

Neodymium is used as a crystal (neodymium-doped yttrium aluminum garnet) in lasers. These ND:YAG lasers have numerous applications. For example, they are used in medicine to treat skin cancers and for laser hair removal; and in industry they are used to cut and weld steel.

Neodymium is used to make specialized goggles for glass blowers.

The metal is also used in a spark producing alloy (misch metal) for cigarette lighter flints.

Neodymium salts are used to color glasses and enamels.

Reaction with air: mild, ⇒ Nd₂O₃
Reaction with 15 M HNO₃: mild, ⇒ Nd(NO₃)₃
Oxide(s): Nd₂O₃
Hydride(s): NdH₂, NdH₃

Reaction with 6 M HCl: mild, ⇒ H₂, NdCl₃
Reaction with 6 M NaOH:
Chloride(s): NdCl₂, NdCl₃

Atomic radius: 185 pm
Ionic radius (2+ ion): 143 pm
Ionic radius (2- ion): pm

Ionic radius (1+ ion): pm
Ionic radius (3+ ion): 112.3 pm
Ionic radius (1- ion): pm

Thermal conductivity: 16.5 W m^-1 K^-1

Electrical conductivity: 1.6 x 10⁶ S m^-1