Dysprosium

Dysprosium (Dy)

Introduction

Dysprosium is a chemical element with an atomic number of 66 in the periodic table of elements. It’s one of the more abundant lanthanide elements found in Earth’s crust, in a concentration of 3 parts per million. Still, it never occurs in its free elemental form.

Classified in the heavy rare-earth elements group (HREE), this soft metal has two valence electrons that enable dysprosium to detect radiation and display high magnetic susceptibility. 

Fact Box

Chemical and Physical Properties of Dysprosium

The symbol in the periodic table of elements: Dy

Atomic number: 66

Atomic weight (mass): 162.50 g.mol-1

Group number: Lanthanides

Period: 6

Color: A lustrous silvery metal

Physical state: Solid at room temperature of 20°C

Half-life: From less than 30 seconds to 144.4 days

Electronegativity according to Pauling: 1.2

Density: 8.55 g/cm−3

Melting point: 1412°C, 2574°F, 1685 K

Boiling point: 2567°C, 4653°F, 2840 K

Van der Waals radius: 175 pm

Ionic radius: N/A

Isotopes: 7

Most characteristic isotope: 164Dy

Electronic shell: [Xe] 4f106s2

The energy of the first ionization: 571.2 kJ.mol-1

The energy of the second ionization: 1124 kJ.mol-1

Discovery date: In 1886 by Paul-Émile Lecoq de Boisbaudran

 

 

Dysprosium is the chemical element of the periodic table with the symbol Dy, atomic number 66, atomic mass of 162.50 g.mol-1, and electron configuration [Xe] 4f106s2. This soft metal classified in the lanthanides family of elements has an electronegativity of 1.2 according to Pauling and an atomic radius of 175 pm. 

 

 

Highly reactive with both water and oxygen, dysprosium reaches its boiling point at 2567°C (4653°F, 2840K), while the melting point is achieved at 1412°C (2574°F, 1685K). At temperatures of 85K (−188.2°C), dysprosium displays ferromagnetic properties that adopt a helical antiferromagnetic state when the temperature reaches above 85 K (−188.2 °C), i.e. it resists demagnetization. Dysprosium tarnishes lightly in moist air, while its luster remains when this soft metal is exposed to dry air.                          

How Was Dysprosium Discovered?

In 1794, yttrium oxide was the chemical substance that had sparked great interest among the scientists working in the field of chemistry. The extensive experiments that were conducted on this chemical lead to not one, but several great discoveries in chemistry. Namely, in 1843 the scientists succeeded to discover erbium (Er), while the consecutive researches opened the way to the discovery of holmium (Ho) in 1878. 

Johan Gadolin’s Contribution to the Discovery of Dysprosium

But, let’s get back to 1794. That year, the Finnish chemist Johan Gadolin (1760 – 1852) attempted to analyze a mineral sample obtained from the small Swedish town of Ytterby. His analysis showed the presence of a new mineral that he referred to as yttrium.

 

In the following experiments conducted on this mineral, Gadolin noticed some impurities. In 1843, two of those trace impurities found in erbia (the oxide of erbium) were recognized by Carl Gustav Mosander (1797 – 1858) as the new elements erbium and terbium, while in 1878, holmium and thulium were discovered in the same manner.

The Successful Research of Paul-Émile Lecoq de Boisbaudran 

In 1886, the French chemist Paul-Émile Lecoq de Boisbaudran (1838 – 1912) followed Gadolin’s findings. De Boisbaudran was intrigued by a piece of mineral containing holmium. He assumed that a new chemical element is ‘hiding’ in this mineral sample.

 

Thus, he embarked on a rather lengthy scientifical journey by attempting to isolate the new element by conducting precipitations with ammonia and oxalate more than 32 times. After this procedure, he would control the fractions spectroscopically. His persistence led him to the highly desired result and the discovery of the chemical element dysprosium (Dy). 

The Innovative Work of Frank Spedding

Until the 1950s, the researchers that tried to isolate this element after de Boisbaudran also didn’t manage to easily isolate the element. It was Frank Spedding (1902 – 1984) who finally succeeded in discovering the ideal technique for the isolation of dysprosium from minerals.

By using ion-exchange chromatography, this Canadian-American chemist managed to separate the dysprosium from the other elements of the analyzed chemical compound. 

How Did Dysprosium Get Its Name?

 

Since dysprosium is not only never found in its pure elemental form in nature, but it’s also hard to be obtained by any other means, the Greek word “dysprositos” (meaning: hard to get) seemed to be the ultimate choice for the name of the new element that required numerous fractional crystallisations in order to be isolated in its pure form. 

Where Can You Find Dysprosium?

 

This rare-earth element can be obtained from the minerals monazite, samarium, bastnäsite, polycrase, blomstrandine, euxenite, xenotime, gadolinite, and fergusonite by reduction of dysprosium trifluoride with calcium metal, or ion exchange and the solvent extraction process. It also occurs in uranium ores and weathered clay deposits (ion-adsorption ore).

 

Nowadays, the dysprosium metal is primarily obtained via an ion exchange process from monazite sand (Ce, La, Th, Nd, Y)PO4). China, Russia, and Malaysia are the three largest producers of dysprosium in the world, while China, the CIS Countries (including Russia), and the United States count as the countries that hold the largest reserves of dysprosium.

 

Dysprosium in Everyday Life

The strong electronic and magnetic properties open wide areas of everyday application for dysprosium. Since it displays a thermal-neutron absorption cross-section, dysprosium is used as one of the main substances in control rods of nuclear reactors. Also, dysprosium iodide is used in the manufacture of halide discharge lamps, where dysprosium gives out a highly intense white light. 

 

The high magnetic susceptibility of this member of the lanthanide family of elements is also applied for:

 

  • Production of sonar sensors;
  • Dysprosium–cadmium chalcogenides are used in scientific researches as sources of infrared radiation;
  • As a semiconductor used in laser diodes; 
  • In high-power and high-frequency applications (mainly used as dysprosium phosphide (DyP));
  • In combination with vanadium, dysprosium is used for the production of laser materials and commercial lighting;
  • In the hybrid and electric vehicles, as an additive to the neodymium-iron-boron magnets in order to increase the operating temperature range;
  • Manufacturing of radiation badges used for detection and monitoring of the radiation exposure;
  • As the main substance in the making of permanent magnets used for wind turbines;
  • In medicine, the dysprosium-165 isotope is used as an injectable administered directly into the joint for the treatment of rheumatoid arthritis;
  • As a coating of the compact discs used for storage of audio, video, and digital data. 
  • Dysprosium in Terfenol-D has found its application in the active noise and vibration cancellation, as well as for the detection of seismic waves.

How Dangerous Is Dysprosium?

Since the biological role of the pure dysprosium is still not thoroughly researched, it’s considered that this chemical has a low level of toxicity based on the properties of dysprosium salts. Also, the dysprosium compounds possess some level of toxicity but are rarely encountered by people in everyday life. The metal particles from dysprosium dust present both a fire and explosion hazard.

Environmental Effects of Dysprosium

So far, the research on this lanthanide hasn’t brought up any viable threats to the environment, or the health of humans, animals, and plants. 

 

Being a rare-earth element, dysprosium is also used in the production of renewed energy sources, hybrid vehicles, pollution control, optics, refrigeration, etc. In this way, the properties of dysprosium as a rare-earth element serve the purpose of a cleaner and healthier environment and contribute to the efforts made against the increasing pollution of environmental air. 

Isotopes of Dysprosium

Dysprosium comes in the form of seven stable isotopes:  156Dy, 158Dy, 160Dy, 161Dy, 162Dy, 163Dy, and 164Dy. There are also twenty-nine radioactive isotopes of this lanthanide. Having a half-life of 144.4 days, 159Dy is the most stable dysprosium isotope. 

 

The following is a tabular representation of the main isotopes of dysprosium:

 

Iso­tope Decay
abun­dance half-life (t1/2) mode pro­duct
154Dy syn 3.0×106 y α 150Gd
156Dy 0.056% stable
158Dy 0.095% stable
160Dy 2.329% stable
161Dy 18.889% stable
162Dy 25.475% stable
163Dy 24.896% stable
164Dy 28.260% stable

 

Source: Wikipedia

List of Dysprosium Compounds 

When dysprosium comes into contact with cold water, it forms the dysprosium hydroxide compound: 

 

                  2 Dy (s) + 6 H2O (l) → 2 Dy(OH)3 (aq) + 3 H2 (g)

 

In contact with oxygen atoms, this chemical readily forms the dysprosium(III) oxide:

 

                                               4Dy + 3 O2 → 2 Dy2O3

 

In reactions with halogens (chlorine, bromine, iodine, and fluorine) dysprosium forms dysprosium halides. Moreover, at temperatures reaching above 200 °C, this lanthanide forms colorful dysprosium salts in a chemical reaction with halides. 

 

2 Dy (s) + 3 Cl2 (g) → 2 DyCl3 (s) / white

2 Dy (s) + 3 Br2 (g) → 2 DyBr3 (s) / white 

                                         2 Dy (s) + 3 I2 (g) → 2 DyI3 (s) / green

                                         2 Dy (s) + 3 F2 (g) → 2 DyF3 (s) / green

 

DyF3 and DyBr3 halides mainly produce yellow salts, while the dysprosium oxide typically gives a white chemical substance as a result of the dysprosium-oxygen reaction. Oxidation states of dysprosium typically vary between +3 and +2. The following is a list comprised of the most common dysprosium compounds:

 

  • Dysprosium acetylacetonate Dy(C5H7O2)3
  • Dysprosium titanate (Dy2Ti2O7)
  • Dysprosium(III) chloride (DyCl3)
  • Dysprosium(III) fluoride (DyF3)
  • Dysprosium(III) hydroxide (Dy(OH)3)
  • Dysprosium(III) oxide (Dy2O3)

5 Interesting Facts and Explanations

  1. Dysprosium is twice more abundant in nature than tin. 
  2. As a result of its high reactivity with O2 and H2O, dysprosium is rarely used in its metal form. 
  3. Together with holmium, dysprosium has the highest magnetic strength of all the periodic system elements. 
  4. Dysprosia, i.e. dysprosium dioxide (2 Dy2O3) is even more magnetic than iron. 
  5. Monazite sand is a substance found in large amounts in various rare-earth elements.