Terminology

Allotropes
Some elements exist in several different structural forms, these are called allotropes.

For more information on Murray Robertson’s image see Uses/Interesting Facts below.

Dysprosium

Discovery date	1886
Discovered by	P.-E. Lecoq de Boisbaudran
Origin of the name	The name is derived from the Greek 'dysprositos', meaning hard to get.
Allotropes	-

162.5

Fact Box Terminology

Group
Elements appear in columns or ‘groups’ in the periodic table. Members of a group typically have similar properties and electron configurations in their outer shell.

Period
Elements are laid out into rows or ‘periods’ so that similar chemical behaviour is observed in columns.

Block
Elements are organised into blocks by the orbital type in which the outer electrons are found. These blocks are named for the characteristic spectra they produce: sharp, principal, diffuse, and fundamental.

Atomic Number
The number of protons in the nucleus.

Atomic Radius/non -bonded (Å)
based on Van der Waals forces (where several isotopes exist, a value is presented for the most prevalent isotope). These values were calculated using a multitude of methods including crystallographic data, gas kinetic collision cross sections, critical densities, liquid state properties, for more details please refer to the CRC Handbook of Chemistry and Physics.

Electron Configuration
The arrangements of electrons above the last (closed shell) noble gas.

Isotopes
Elements are defined by the number of protons in its centre (nucleus), whilst the number of neutrons present can vary. The variations in the number of neutrons will create elements of different mass which are known as isotopes.

Melting Point (^oC)
The temperature at which the solid-liquid phase change occurs.

Melting Point (K)
The temperature at which the solid-liquid phase change occurs.

Melting Point (^oF)
The temperature at which the solid-liquid phase change occurs.

Boiling Point (^oC)
The temperature at which the liquid-gas phase change occurs.

Boiling Point (K)
The temperature at which the liquid-gas phase change occurs.

Boiling Point (^oF)
The temperature at which the liquid-gas phase change occurs.

Sublimation
Elements that do not possess a liquid phase at atmospheric pressure (1 atm) are described as going through a sublimation process.

Density (kgm^-3)
Density is the weight of a substance that would fill 1 m³ (at 298 K unless otherwise stated).

Relative Atomic Mass
The mass of an atom relative to that of Carbon-12. This is approximately the sum of the number of protons and neutrons in the nucleus. Where more than one isotope exists the value given is the abundance weighted average.

Key Isotopes (% abundance)
An element must by definition have a fixed number of protons in its nucleus, and as such has a fixed atomic number, however variants of an element can exist with differing numbers of neutrons, and hence a different atomic masses (e.g. ¹²C has 6 protons and 6 neutrons and ¹³C has 6 protons and 7 neutrons).

CAS number
The Chemical Abstracts Service registry number is a unique identifier of a particular chemical, designed to prevent confusion arising from different languages and naming systems (where several isotopes exist, a value is presented for the most prevalent isotope).

Fact Box

Group	Lanthanides	Melting point	1412 ^oC, 2573.6 ^oF, 1685.15 K
Period	6	Boiling point	2567 ^oC, 4652.6 ^oF, 2840.15 K
Block	f	Density (kg m^-3)	8531
Atomic number	66	Relative atomic mass	162.5
State at room temperature	Solid	Key isotopes	¹⁶⁴Dy
Electron configuration	[Xe] 4f¹⁰6s²	CAS number	7429-91-6
ChemSpider ID	22355	ChemSpider is a free chemical structure database

Interesting Facts terminology

Image Explanation

Murray Robertson is the artist behind the images which make up Visual Elements. This is where the artist explains his interpretation of the element and the science behind the picture.

Natural Abundance

Where this element is most commonly found in nature.

Biological Roles

The elements role within the body of humans, animals and plants. Also functionality in medical advancements both today and years ago.

Appearance

The description of the element in its natural form.

Uses / Interesting Facts

Image explanation

An image reflecting the use of the element in nuclear reactors.

Appearance

A silvery metallic element. Some is used for making alloys for magnets, but as a pure metal it is useless because it reacts rapidly with water and air.

Uses

Dysprosium's main use is in permanent magnets. It is used as an alloying addition to neodymyium based magents due to its resisitance to demagnetisation at eleveated temperatures. This property is important for magnets used in motors or generators. Due to the use of these magnets in wind turbines and electrical vehicles, demand for dysprosium is growing rapidly. A dysprosium oxide-nickel cement is used to in nuclear reactor control rods, and has the property of absorbing neutrons readily without swelling or contracting under prolonged neutron bombardment.

Biological role

Dysprosium has no known biological role, and has low toxicity.

Natural abundance

In common with many other lanthanides, dysprosium is found in the minerals monazite and bastnaesite, and in smaller quantities in several other minerals such as xenotime and fergusonite. It can be extracted from these minerals by ion exchange and solvent extraction. It can also be prepared by the reduction of the trifluoride with calcium metal.

Atomic Data Terminology

Atomic radius/non -bonded (Å)
Based on Van der Waals forces (where several isotopes exist, a value is presented for the most prevalent isotope). These values were calculated using a multitude of methods including crystallographic data, gas kinetic collision cross sections, critical densities, liquid state properties,for more details please refer to the CRC Handbook of Chemistry and Physics.

Electron affinity (kJ mol^-1)
The energy released when an additional electron is attached to the neutral atom and a negative ion is formed (where several isotopes exist, a value is presented for the most prevalent isotope). *

Electronegativity (Pauling scale)
The degree to which an atom attracts electrons towards itself, expressed on a relative scale as a function bond dissociation energies, E_d in eV. χ_A - χ_B =(eV)-1/2sqrt(E_d(AB)-[E_d(AA)+E_d(BB)]/2), with χ_H set as 2.2 (where several isotopes exist, a value is presented for the most prevalent isotope).

1^st Ionisation energy (kJ mol^-1)
The minimum energy required to remove an electron from a neutral atom in its ground state (where several isotopes exist, a value is presented for the most prevalent isotope).

Covalent radius (Å)
The size of the atom within a covalent bond, given for typical oxidation number and coordination (where several isotopes exist, a value is presented for the most prevalent isotope). ***

Atomic Data

Atomic radius, non-bonded (Å)	2.310	Covalent radius (Å)	1.8
Electron affinity (kJ mol^-1)	Unknown	Electronegativity (Pauling scale)	1.220
Ionisation energies (kJ mol^-1)	1^st 573.016 2^nd 1125.983 3^rd 2199.864 4^th 4001.244 5^th - 6^th - 7^th - 8^th -

Mining/Sourcing Information

Data for this section of the data page has been provided by the British Geological Survey. To review the full report please click here or please look at their website here.

Key for numbers generated

Governance indicators

1 (low) = 0 to 2

2 (medium-low) = 3 to 4

3 (medium) = 5 to 6

4 (medium-high) = 7 to 8

5 (high) = 9

Reserve base distribution

1 (low) = 0 to 30 %

2 (medium-low) = 30 to 45 %

3 (medium) = 45 to 60 %

4 (medium-high) = 60 to 75 %

5 (high) = 75 %

(Where data are unavailable an arbitrary score of 2 was allocated. For example, Be, As, Na, S, In, Cl, Ca and Ge are allocated a score of 2 since reserve base information is unavailable. Reserve base data are also unavailable for coal; however, reserve data for 2008 are available from the Energy Information Administration (EIA).)

Production Concentration

1 (low) = 0 to 30 %

2 (medium-low) = 30 to 45 %

3 (medium) = 45 to 60 %

4 (medium-high) = 60 to 75 %

5 (high) = 75 %

Crustal Abundance

1 (low) = 100 to 1000 ppm

2 (medium-low) =10 to 100 ppm

3 (medium) = 1 to 10 ppm

4 (medium-high) = 0.1 to 1 ppm

5 (high) = 0.1 ppm

(Where data are unavailable an arbitrary score of 2 was allocated. For example, He is allocated a score of 2 since crustal abundance data is unavailable.)

Explanations for terminology

Crustal Abundance (ppm)

The abundance of an element in the Earth's crust in parts-per-million (ppm) i.e. The number of atoms of this element per 1 million atoms of crust.

Sourced

The country with the largest reserve base.

Reserve Base Distribution

This is a measure of the spread of future supplies, recording the percentage of a known resource likely to be available in the intermediate future (reserve base) located in the top three countries.

Production Concentrations

This reports the percentage of an element produced in the top three countries. The higher the value, the larger risk there is to supply.

Total Governance Factor

The World Bank produces a global percentile rank of political stability. The scoring system is given below, and the values for all three production countries were summed.

Relative Supply Risk Index

The Crustal Abundance, Reserve Base Distribution, Production Concentration and Governance Factor scores are summed and then divided by 2, to provide an overall Relative Supply Risk Index.

Supply Risk

Scarcity factor	8.0
Country with largest reserve base	China
Crustal abundance (ppm)	0.3
Leading producer	China
Reserve base distribution (%)	59.30
Production concentration (%)	97.40
Total governance factor(production)	8

Top 3 countries (mined)	1) China 2) USA 3) CIS
Top 3 countries (production)	1) China 2) Russia 3) Brazil

Oxidation states/ Isotopes

Key for Isotopes

Half Life
	y	years
	d	days
	h	hours
	m	minutes
	s	seconds
Mode of decay
	α	alpha particle emission
	β	negative beta (electron) emission
	β+	positron emission
	EC	orbital electron capture
	sf	spontaneous fission
	ββ	double beta emission
	ECEC	double orbital electron capture

Terminology

Common Oxidation states
The oxidation state of an atom is a measure of the degree of oxidation of an atom. It is defined as being the charge that an atom would have if all bonds were ionic. Free atoms have an oxidation state of 0, and the sum of oxidation numbers within a substance must equal the overall charge.

Important Oxidation states
The most common oxidation states of an element in its compounds.

Oxidation States / Isotopes

Common oxidation states	3
Isotopes	Isotope	Atomic mass	Natural abundance (%)	Half life	Mode of decay
	¹⁵⁶Dy	155.924	0.056	-	-
	¹⁵⁸Dy	157.924	0.095	-	-
	¹⁶⁰Dy	159.925	2.329	-	-
	¹⁶¹Dy	160.927	18.889	-	-
	¹⁶²Dy	161.927	25.475	-	-
	¹⁶³Dy	162.929	24.896	-	-
	¹⁶⁴Dy	163.929	28.26	-	-

Pressure and Temperature - Advanced Terminology

Molar Heat Capacity (J mol^-1 K^-1)

Molar heat capacity is the energy required to heat a mole of a substance by 1 K.

Young's modulus (GPa)

Young's modulus is a measure of the stiffness of a substance, that is, it provides a measure of how difficult it is to extend a material, with a value given by the ratio of tensile strength to tensile strain.

Shear modulus (GPa)

The shear modulus of a material is a measure of how difficult it is to deform a material, and is given by the ratio of the shear stress to the shear strain.

Bulk modulus (GPa)

The bulk modulus is a measure of how difficult to compress a substance. Given by the ratio of the pressure on a body to the fractional decrease in volume.

Vapour Pressure (Pa)

Vapour pressure is the measure of the propensity of a substance to evaporate. It is defined as the equilibrium pressure exerted by the gas produced above a substance in a closed system.

Pressure / Temperature - Advanced

Molar heat capacity
(J mol^-1 K^-1)

28.16

Young's modulus (GPa)

Unknown

Shear modulus (GPa)

Unknown

Bulk modulus (GPa)

Unknown

Vapour pressure

Temperature (K)

400

600

800

1000

1200

1400

1600

1800

2000

2200

2400

Pressure (Pa)

1.54
x 10^-8

8.21
x 10^-5

2.41
x 10^-2

1.36

27.5

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History

Elements and Periodic Table History

Dysprosium was discovered in 1886 by Paul-Émile Lecoq de Boisbaudran at Paris. Its discovery came as a result of research into yttrium oxide, first made in 1794, and from which other rare earths (aka lanthanoids) were subsequently to be extracted, namely erbium in 1843, then holmium in 1878, and finally dysprosium. De Boisbaudran’s method had involved endless precipitations carried out on the marble slab of his fireplace at home.

Pure samples of dysprosium were not available until Frank Spedding and co-workers at Iowa State University developed the technique of ion-exchange chromatography around 1950. From then on it was possible to separate the rare earth elements in a reliable and efficient manner, although that method of separation has now been superseded by liquid-liquid exchange technology.

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Podcasts

Listen to Dysprosium Podcast

Transcript :

Chemistry in its element - dysprosium

(Promo)

You're listening to Chemistry in its element brought to you by Chemistry World, the magazine of the Royal Society of Chemistry

(End promo)

Meera Senthilingam

This week an element which played hard to get but once caught gave a wide range of chemical applications. Simon Cotton

Simon Cotton

If you study a timeline of the discovery of the chemical elements, you see that new elements have often been discovered in clusters, in parallel with some other breakthrough in science. Obviously, the transuranium elements were a spin-off from developments in radiochemistry accompanying the Manhattan project - the second world war project to develop the first atomic bomb. Likewise the noble gases could easily be separated once cryogenics became feasible, thanks to the invention of Dewar's flask.

In the mid-19th century, Bunsen and Kirchhoff found that different elements emitted light of different frequencies when hot, and used this to identify new elements such as rubidium and caesium. Paul Émile Lecoq de Boisbaudran was one of the first people to exploit this new technique. He came from Cognac in France, so you will not be surprised to learn that his family made cognac. In 1875, he identified gallium from two spectroscopic lines in the spectrum of a sample of zinc blende from the Pyrénées, and isolated the element later that year, thus filling one of the gaps left in the Periodic Table by Mendeleev. At that time, scientists were using improved techniques such as fractional crystallisation to obtain the individual lanthanides from mixtures. In 1879 Lecoq went on to extract pure samarium from the mineral samarskite whilst in 1886 he was the first person to identify dysprosium by separating its oxide from holmium oxide. To achieve the separation, he used precipitations with ammonia and with oxalate, checking the fractions spectroscopically. It took him over 30 goes to do this, so he named the element accordingly, from the Greek word, dysprositos, meaning "hard to get at".

All the lanthanides are rather similar to each other chemically, showing gradations in properties from one end of the series to the other, but electronic and magnetic properties which depend upon the number of electrons, vary a lot from one lanthanide to its neighbour, giving each lanthanide its own particular uses.

One very unusual application for dysprosium is in the alloy Terfenol-D, which also contains terbium and iron. It is a magnetostrictive material, meaning that when it is put into a magnetic field, it changes shape, reversibly. This has found applications in ships' sonar systems (underwater radar using soundwaves) and in all sorts of sensors and transducers.

Along with a little caesium iodide and mercury bromide, dysprosium iodide is used in Medium Source Rare Earth Lamps (otherwise known as MSRs). These are discharge lamps where the dysprosium iodide emits over a range of frequencies, giving a good colour rendering. Caesium iodide helps broaden the emission whilst the mercury bromide reduces corrosion of the bulb and of the tungsten electrodes. These have applications including the film industry; the lamps have a high luminous efficiency whilst they can be dimmed appreciably whilst still maintaining the same "colour temperature".

Like other heavier lanthanides, dysprosium has a lot of unpaired electrons, giving both the metal and its ions a high magnetic susceptibility. This has led to applications in data storage devices, such as compact discs.

Dysprosium has a high thermal neutron absorption cross-section, meaning that it is very good at absorbing neutrons. Because of this, it is used to make the control rods that are put into nuclear reactors to absorb excess neutrons and stop fission reactions getting out of control.

There seem to be a lot of dys- words around at the start of the 21st century, They have the Greek prefix for abnormal or bad - dyslexic, dyspepsia and dysfunctional spring to mind. Dysprosium's not like that, it has many applications and as time goes on it will have even more.

Meera Senthilingam

So elementally changing the connotations of the greek prefix. That was Simon Cotton explaining the widely applied chemistry of dysprosium. Now next week, a mythological element that appears to be weeping.

Jon Steed

The element was christened after Niobe the daughter of Tantalus in greek mythology. Niobe had a fairly hard time of it. She was foolish enough to suggest that rather than worshipping invisible gods, it might be a nice idea to appreciate real people for a change. The greek gods weren't very forgiving of this kind of hubris and as a punishment killed if not all then most of her twelve children - the Niobids. As a result Niobe fled to mount Sipylus and was turned to stone. There is to this day a rock formation in the Aegean region of Turkey termed the weeping rock that resembles a woman's face purportably Niobe's. Water seeps through the porous limestone of the weeping rock and is said to resemble Niobe's unceasing tears at the fate of the Niobids.

Meera Senthilingam

And move away from the tears to find out the colourful and superconducting chemistry of the element niobium with Jon Steed in next week's Chemistry in its Element. Until then I'm Meera Senthilingam, thanks for listening and goodbye.

(Promo)

Chemistry in its element is brought to you by the Royal Society of Chemistry and produced by thenakedscientists dot com. There's more information and other episodes of Chemistry in its element on our website at chemistryworld dot org forward slash elements.

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References

Images: Visual Elements © Murray Robertson 2011
Mining and Sourcing data: British Geological Survey – natural environment research council.
Text: John Emsley Nature’s Building Blocks: An A-Z Guide to the Elements, Oxford University Press, 2nd Edition, 2011.
Additional information for platinum, gold, neodymium and dysprosium obtained from Material Value Consultancy Ltd www.matvalue.com
Data: CRC Handbook of Chemistry and Physics, CRC Press, 92nd Edition, 2011.
G. W. C. Kaye and T. H. Laby Tables of Physical and Chemical Constants, Longman, 16th Edition, 1995.
Members of the RSC can access these books through our library.

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