Neodymium

Neodymium (Nd)

Introduction

Neodymium is a chemical element with the atomic number 60 in the periodic table. Despite being classified as a rare-earth element, neodymium is widely distributed in Earth’s crust. It mainly occurs in the mineral ores. As a member of the lanthanide series of periodic table elements, this rare-earth metal has three valence electrons that help neodymium to form many compounds characterized with rich and bold colors. 

Element 60 is a part of the strongest magnet in the world. The Nd-Fe-B magnet is widely used in the industrial branches dealing with electrical and electronic devices, while the neodymium lasers have a significant role in medicine regarding cancer treatments.

Fact Box

Chemical and Physical Properties of Neodymium

The symbol in the periodic table of elements: Nd

Atomic number: 60

Atomic weight (mass): 144.2 g.mol-1

Group (number): Lanthanides

Period: 6 (f-block)

Color: A silvery-white metal

Physical state: Solid at 20°C

Half-life: From less than 70 seconds to 7×1018 years

Electronegativity according to Pauling: 1.14

Density: 7.0 g cm-3

Melting point: 1016°C, 1861°F, 1289 K

Boiling point: 3074°C, 5565°F, 3347 K

Van der Waals radius: 0.181 nm

Ionic radius: N/A

Isotopes: 37

Most characteristic isotope: 142Nd

Electronic shell: [Xe] 4f46s2

The energy of the first ionization: 533 kJ.mol-1

The energy of the second ionization: 1040 kJ.mol-1

The energy of the third ionization: 2130 kJ.mol-1

Discovery date: In 1885 by Carl Auer von Welsbach

With the periodic table symbol Nd, atomic number 60, atomic mass of 144.2 g.mol-1, and electron configuration [Xe] 4f46s2, neodymium is soft, ductile, and malleable metal with a bright and silvery lustrous appearance. It reaches its boiling point at 3074°C, 5565°F, 3347 K, while the melting point is achieved at 1016°C, 1861°F, 1289 K. This member of the lanthanide family of elements in the periodic table has an electronegativity of 1.14 according to Pauling, whereas the atomic radius according to van der Waals is 0.181 nm. 

Upon exposure to air, neodymium tarnishes extremely fast, but the formed coating does not protect this metal from further oxidative processes.  Having a hexagonal to body-centered cubic structure, neodymium occurs in two allotropic forms –  α and β. The sharp absorption capacity of neodymium changes the color of glass under different lighting conditions. Namely, upon oxidation, neodymium forms reactions that produce pink, purple, blue, and yellow compounds. In these compounds, neodymium typically adopts the +2, +3, and +4 oxidation states.

How Was Neodymium Discovered?

Austrian scientist Carl Auer von Welsbach (1858-1929) is the first scientist who has succeeded in identifying this rare earth element in a mixture labeled as didymium. His interest in didymium was sparked by the Swedish chemist Carl Mosander (1797-1858), who had incorrectly identified this mineral. 

Wanting to isolate all elements of this compound, von Welsbach performed fractional crystallization of the double ammonium nitrate tetrahydrates derived from nitric acid. This method was invented by von Welsbach himself. After conducting 167 crystallizations, the results of his chemical trial helped the Austrian chemist to clearly isolate two different substances from the didymium sample – a bluish-lilac substance that he called neodymium, and its green ‘twin’ – praseodymium. 

On 18 June 1885, Carl Auer von Welsbach informed the Vienna Academy of Sciences of his discovery. While the German chemist Robert Wilhelm Eberhard Bunsen recognized von Welsbach’s efforts and accepted the results of his work, the other scientists remained skeptical due to the limited experimental technology they had at their disposal at the time. 

How Did Neodymium Get Its Name?

This chemical element got its name after the Greek words ‘neos’ and ‘didymos’, which mean ‘a new twin’. This points out the relation of element 60 to praseodymium – the element that was recognized alongside neodymium by the Austrian discoverer Carl Auer von Welsbach. 

Where Can You Find Neodymium?

Being classified as a rare earth element, neodymium never occurs naturally in its pure, elemental form. Only yttrium, lanthanum, and cerium are more plentiful rare-earth elements than neodymium.

Neodymium is usually traced in the minerals monazite and bastnäsite, but it’s extremely difficult to be extracted from the mineral ores containing other rare earth elements. The element 60 can be isolated from the minerals monazite and bastnäsite by the process of ion exchange, or by solvent extraction of the substance. In addition, neodymium can also be obtained by reducing anhydrous halides (like NdF3) with calcium metal.

The largest neodymium mines are located in China, the United States, Australia, Sri Lanka, Brazil, and India. 

Neodymium in Everyday Life

Before any use, neodymium always undergoes a process of refinement, which is performed by an ion-exchange purification of the substance. The following instances show some applications of neodymium:

  • The strongest permanent magnets are made of neodymium (Nd2Fe14B). Neodymium magnets (NIB) are a more economical, lighter, and stronger variant than the samarium-cobalt magnets. Made of magnetic material constituting neodymium, iron, and boron, these magnets are also plated in nickel–copper-nickel to avoid corrosion. Furthermore, the strength of the magnetic properties of a neodymium magnet is graded according to its maximum energy product, i.e. (BH)max. For instance, the strongest neodymium magnet currently is graded with N52, while the N35 is the neodymium magnet with the least powerful magnetic performance. 
  • The strength and size of volcanic eruptions can be predicted by scanning for neodymium isotopes; because their isotope combinations vary immensely. According to an analysis published in the New York Times Magazine, the bigger the eruption – the larger the neodymium concentration in the magma is. The results obtained from the analysis of the larger volcano eruptions have proved the fact that they had a higher ratio of neodymium-143 to neodymium-144. This finding gives reason for the scientists to claim that the big eruptions come from a deeper layer of the Earth, where the naturally occurring and most abundant neodymium-144 can be found;
  • Neodymium-doped yttrium aluminum garnet laser (Nd:YAG laser) used the Nd:YAG neodymium compound as a laser medium for a solid-state laser. It’s a four-level laser system made of an energy source, active medium, and optical resonator. This type of laser is widely used in medicine for performing Lasik surgery and laser spectroscopy. It’s also applied in various scientific researches. Apart from low power consumption and high precision, the neodymium-doped yttrium aluminum garnet lasers also display good thermal and mechanical properties;
  • Together with didymium, this chemical element is a component of the didymium glass. This special type of glass is used for making welding and glass blowering goggles. It’s also applied in the manufacturing of tanning booth glass because this chemical element blocks the ultraviolet rays, but permits the tanning rays;
  • Electric motors of hybrid and electric automobiles as well as the electricity generators of some commercial wind turbine designs use neodymium as one of the main components in their construction;
  • Neodymium salts are used as a coloring agent of enamels;
  • Neodymium oxide, also referred to as neodymia, is typically used for glass and capacitors. Neodymium colors the glass in various nuances that encompass pure violet, wine-red, and warm grey hue;
  • Furthermore, neodymium glass is applied in the manufacturing of lasers, which are widely used in laser eye surgery, cosmetic surgery, as well as in the treatment of skin cancers;
  • Neodymium is frequently used in fluorescent lamps, energy-saving lamps, color televisions, for the light transmitted through neodymium glasses displays unusually sharp bands of absorption by which spectral lines may be calibrated. This is also the reason why this chemical is used in astronomical work, too.

How Dangerous Is Neodymium?

Neodymium is a chemical element with low to moderate toxicity. However, when combined with other chemical elements in a compound, that neodymium compound might produce some extremely toxic and dangerous effects. The colorful salts and dust of this lanthanide can trigger irritation to the eyes and the mucous membranes, while the soluble salts of neodymium are slightly toxic when ingested. The metal dust of this chemical element also presents a combustion and explosion hazard.

Occupational long-term exposure to the pure, elemental form of neodymium can lead to adverse health effects, affecting the lung and kidneys the most. Lung embolism is the most characteristic disease occurring as a result of overexposure to this lanthanide element.

Environmental Effects of Neodymium

The industrial wastes that contain particles of neodymium may contaminate the air, soil, surface waters, and plants. Other than that, this chemical element has no biological role that could influence the environment or the living organisms, including humans. 

Isotopes of Neodymium

Five stable isotopes form the naturally occurring neodymium: 142Nd, 143Nd, 145Nd, 146Nd, and 148Nd. Among them, neodymium-142 is the most abundant form of this chemical element, with 27.2 % of natural occurrence.

144Nd and 150Nd are the two radioactive isotopes of element 60 with the longest half-life: neodymium-144 goes through an alpha decay with a half-life (t1/2) of 2.29×1015 years, while neodymium-150 radioisotope goes through double beta decay with t1/2 = 7×1018 years of half-life. 

Nuclide

[n 1]

 Z N Isotopic mass (Da)

[n 2][n 3]

 Half-life

[n 4][n 5]

 Decay

mode

[n 6]

 Daughter

isotope

[n 7]

 Spin and

parity

[n 8][n 5]

 Natural abundance (mole fraction)
Excitation energy[n 5] Normal proportion Range of variation
124Nd 60 64 123.95223(64)# 500# ms 0+
125Nd 60 65 124.94888(43)# 600(150) ms 5/2(+#)
126Nd 60 66 125.94322(43)# 1# s [>200 ns] β+ 126Pr 0+
127Nd 60 67 126.94050(43)# 1.8(4) s β+ 127Pr 5/2+#
β+, p (rare) 126Ce
128Nd 60 68 127.93539(21)# 5# s β+ 128Pr 0+
β+, p (rare) 127Ce
129Nd 60 69 128.93319(22)# 4.9(2) s β+ 129Pr 5/2+#
β+, p (rare) 128Ce
130Nd 60 70 129.92851(3) 21(3) s β+ 130Pr 0+
131Nd 60 71 130.92725(3) 33(3) s β+ 131Pr (5/2)(+#)
β+, p (rare) 130Ce
132Nd 60 72 131.923321(26) 1.56(10) min β+ 132Pr 0+
133Nd 60 73 132.92235(5) 70(10) s β+ 133Pr (7/2+)
134Nd 60 74 133.918790(13) 8.5(15) min β+ 134Pr 0+
135Nd 60 75 134.918181(21) 12.4(6) min β+ 135Pr 9/2(–)
136Nd 60 76 135.914976(13) 50.65(33) min β+ 136Pr 0+
137Nd 60 77 136.914567(12) 38.5(15) min β+ 137Pr 1/2+
138Nd 60 78 137.911950(13) 5.04(9) h β+ 138Pr 0+
139Nd 60 79 138.911978(28) 29.7(5) min β+ 139Pr 3/2+
140Nd 60 80 139.90955(3) 3.37(2) d EC 140Pr 0+
141Nd 60 81 140.909610(4) 2.49(3) h β+ 141Pr 3/2+
142Nd 60 82 141.9077233(25) Stable 0+ 0.272(5) 0.2680–0.2730
143Nd[n 9] 60 83 142.9098143(25) Observationally Stable[n 10] 7/2− 0.122(2) 0.1212–0.1232
144Nd[n 9][n 11] 60 84 143.9100873(25) 2.29(16)×1015 y α 140Ce 0+ 0.238(3) 0.2379–0.2397
145Nd[n 9] 60 85 144.9125736(25) Observationally Stable[n 12] 7/2− 0.083(1) 0.0823–0.0835
146Nd[n 9] 60 86 145.9131169(25) Observationally Stable[n 13] 0+ 0.172(3) 0.1706–0.1735
147Nd[n 9] 60 87 146.9161004(25) 10.98(1) d β− 147Pm 5/2−
148Nd[n 9] 60 88 147.916893(3) Observationally Stable[n 14] 0+ 0.057(1) 0.0566–0.0578
149Nd[n 9] 60 89 148.920149(3) 1.728(1) h β− 149Pm 5/2−
150Nd[n 9][n 11] 60 90 149.920891(3) 6.7(7)×1018 y β−β− 150Sm 0+ 0.056(2) 0.0553–0.0569
151Nd 60 91 150.923829(3) 12.44(7) min β− 151Pm 3/2+
152Nd 60 92 151.924682(26) 11.4(2) min β− 152Pm 0+
153Nd 60 93 152.927698(29) 31.6(10) s β− 153Pm (3/2)−
154Nd 60 94 153.92948(12) 25.9(2) s β− 154Pm 0+
155Nd 60 95 154.93293(16)# 8.9(2) s β− 155Pm 3/2−#
156Nd 60 96 155.93502(22) 5.49(7) s β− 156Pm 0+
157Nd 60 97 156.93903(21)# 2# s [>300 ns] β− 157Pm 5/2−#
158Nd 60 98 157.94160(43)# 700# ms [>300 ns] β− 158Pm 0+
159Nd 60 99 158.94609(54)# 500# ms β− 159Pm 7/2+#
160Nd 60 100 159.94909(64)# 300# ms β− 160Pm 0+
161Nd 60 101 160.95388(75)# 200# ms β− 161Pm 1/2−#

Source: Wikipedia

List of Neodymium Compounds

When forming a compound, neodymium mostly adopts the oxidation state of +3. Typically, the compounds in which neodymium can be found as one of the components are halides, oxides, sulphides, chlorides, and nitrides by form. 

Neodymium salts are strongly colored compounds, displaying pink and pale purple as a dominant color. The most common neodymium compounds include: 

 

  • Neodymium(III) Oxide
  • Neodymium Selenide
  • Neodymium Hydroxide
  • Neodymium(II) Chloride
  • Neodymium(II) Iodide
  • Neodymium(III) Iodide
  • Neodymium(III) Chloride
  • Neodymium Tribromide
  • Neodymium(III) Carbide
  • Neodymium(III) Sulfide
  • Neodymium(II) Sulfide
  • Neodymium(III) Nitrate
  • Neodymium(III) Sulfate
  • Neodymium(III) Nitride
  • Neodymium(III) Chloride Hexahydrate
  • Neodymium-doped yttrium lithium fluoride
  • Neodymium-doped yttrium orthovanadate
  • Monazite-(Nd)
  • Nd:GdVO4
  • Nd:YAG laser
  • Nd:YCOB
  • Neodymium aluminium borate
  • Neodymium fluoride
  • Didymium
  • Astrocyanite-(Ce)
  • Neodymium nitrate

5 Interesting Facts and Explanations

  1. This neodymium-iron-boron magnet was the first and the strongest type of rare-earth magnet that has been used and simultaneously commercialized by two of the world’s biggest companies: General Motors (USA) and Sumitomo Specialty Metals (Japan). 
  2. Neodymium’s use in magnets enables miniaturization of many electronic devices, such as mobile phones, computers, microphones, loudspeakers, electronic musical instruments, etc. 
  3. There’s about 18% of neodymium in mischmetal – an alloy of rare-earth elements used for cigarette lighter flints.
  4. With about 38 mg/kg occurrence in Earth’s crust as a part of some mineral formations, neodymium is the second most abundant rare-earth element after cerium.
  5. The pure elemental form of neodymium metal was first isolated by H. Kremers in 1925.