Periodic Table > Scandium
 

Terminology


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


For more information on Murray Robertson’s image see Uses and properties facts below.

 

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 Melting point 1541 oC, 2805.8 oF, 1814.15 K 
Period Boiling point 2836 oC, 5136.8 oF, 3109.15 K 
Block Density (kg m-3) 2992 
Atomic number 21  Relative atomic mass 44.956  
State at room temperature Solid  Key isotopes 45Sc 
Electron configuration [Ar] 3d14s2  CAS number 7440-20-2 
ChemSpider ID 22392 ChemSpider is a free chemical structure database
 

Uses and properties 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 and properties

 
Image explanation
The element’s name is derived from the Latin name for Scandinavia. The image reflects this with an ancient Scandinavian figurine and carved runic standing stone.
Appearance

A silvery metal that tarnishes in air, burns easily and reacts with water.

Uses

Scandium is mainly used for research purposes. It has, however, great potential because it has almost as low a density as aluminium and a much higher melting point. An aluminium-scandium alloy has been used in Russian MIG fighter planes, high-end bicycle frames and baseball bats.

Scandium iodide is added to mercury vapour lamps to produce a highly efficient light source resembling sunlight. These lamps help television cameras to reproduce colour well when filming indoors or at night-time.

The radioactive isotope scandium-46 is used as a tracer in oil refining to monitor the movement of various fractions. It can also be used in underground pipes to detect leaks.

Biological role
Scandium has no known biological role. It is a suspected carcinogen.
Natural abundance

Scandium is very widely distributed, and occurs in minute quantities in over 800 mineral species. It is the main component of the very rare and collectable mineral thortveitite, found in Scandinavia.

Scandium can be recovered from thortveitite or extracted as a by-product from uranium mill tailings (sandy waste material). Metallic scandium can be prepared by reducing the fluoride with calcium metal. It can also be prepared by electrolysing molten potassium, lithium and scandium chlorides, using electrodes of tungsten wire and molten zinc.

 
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, Ed in eV. χA - χB =(eV)-1/2sqrt(Ed(AB)-[Ed(AA)+Ed(BB)]/2), with χH set as 2.2 (where several isotopes exist, a value is presented for the most prevalent isotope).


1st 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) 2.150 Covalent radius (Å) 1.59
Electron affinity (kJ mol-1) 18.133 Electronegativity
(Pauling scale)
1.360
Ionisation energies
(kJ mol-1)
 
1st
633.088
2nd
1234.989
3rd
2388.653
4th
7090.644
5th
8842.874
6th
10678.988
7th
13314.965
8th
15254.319
 

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 Unknown
Country with largest reserve base Unknown
Crustal abundance (ppm) Unknown
Leading producer Unknown
Reserve base distribution (%) Unknown
Production concentration (%) Unknown
Total governance factor(production) Unknown
Top 3 countries (mined)
  • Unknown
Top 3 countries (production)
  • Unknown
 

Oxidation states and 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.


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.

Oxidation states and isotopes

 
Common oxidation states 3
Isotopes Isotope Atomic mass Natural abundance (%) Half life Mode of decay
  45Sc 44.956 100
 

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 and temperature data – advanced

 
Molar heat capacity
(J mol-1 K-1)
25.52 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)
- - - 6.31
x 10-8
1.29
x 10-4
0.03 1.8 43.6 91.3 - -
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History

In 1869, Mendeleev noticed that there was a gap in atomic weights between calcium (40) and titanium (48) and predicted there was an undiscovered element of intermediate atomic weight. He forecast that its oxide would be X2O3. It was discovered as scandium in 1879, by Lars Frederik Nilson of the University of Uppsala, Sweden. He extracted it from euxenite, a complex mineral containing eight metal oxides. He had already extracted erbium oxide from euxenite, and from this oxide he obtained ytterbium oxide and then another oxide of a lighter element whose atomic spectrum showed it to be an unknown metal. This was the metal that Mendeleev had predicted and its oxide was Sc2O3.


Scandium metal itself was only produced in 1937 by the electrolysis of molten scandium chloride.

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Podcasts

Listen to Scandium Podcast
Transcript :

Chemistry in its element - scandium


(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 whose existence had been expected, Here's David Linsay.

David Lindsay

Scandium, atomic number 21. It is the first of the transition metals, and its discovery is entwined with that of vertical neighbours yttrium and lanthanum. The Swedish island of Resarö, near Stockholm, became a hotbed of elemental discovery in the late eighteenth, and early nineteenth, centuries. A quarry near the village of Ytterby yielded two different mineral ores, from which the seventeen so-called "rare earth" elements were eventually identified, those being scandium, yttrium and the fifteen lanthanide elements.   

In 1788, a Lieutenant Arrhenius found an unusual black rock near the town of Ytterby. He passed this on to the famous Finnish scientist Johan Gadolin, and the story of the discovery of the rare earths began. 

In 1879, Lars Nilson, isolated the oxide of a new metal element from the minerals gadolinite and euxenite. Nilson was a student of the legendary Jacob Berzelius, himself discoverer of many elements. Nilson named this oxide scandia, after Scandinavia. The discovery of this element was especially notable, as, seven years previously, Mendeleev had used his periodic table to predict the existence of ten as yet unknown elements, and for four of these, he predicted in great detail the properties they should have. One of these four, Mendeleev predicted, should have properties very similar to boron, and he named this element "ekaboron", meaning "like boron". The metal of this new oxide, scandia, was indeed found to have similar properties to this "ekaboron", thus demonstrating the power of Mendeleev's construction. For example, Mendeleev predicted the element's molecular weight would be 44 and that it would form one oxide with formula Eb2O3; scandium has molecular weight 45, and forms scandium oxide, Sc2O3. Some of Mendeleev's predictions were even more detailed. He predicted that the carbonate of ekaboron would not be soluble in water, which scandium carbonate is not. He even made a prediction related to the discovery of the element - that it would not be discovered spectroscopically. Indeed, scandium produces no spectroscopic lines, so could not be identified by this method of analysis. However, it was another Swedish chemist, Per Theodor Cleve, who was also working on the rare earths, who noticed the similarity between Nilson's new element, and the ekaboron predicted by Mendeleev. Despite the discovery of the oxide of this new element, it would take almost another sixty years until pure, elemental scandium was prepared, being made by electrolysis of scandium chloride in the presence of lithium and potassium, at high temperature. 

Scandium is the first of the transition metals. Many of the transition metals exhibit a very rich and varied chemistry, due to the fact that they can exist in a wide variety of oxidation states. Scandium, however, is limited to the plus three oxidation state, meaning its chemistry is not quite as diverse as some of its transition metal counterparts. 

Scandium is very much a late starter compared to many of the other elements, due to its relatively low occurrence and the difficulty in obtaining it from its ores. For example, it wasn't until the 1960s when the first pound, or 450 grams, of high purity scandium was obtained. Compounds of scandium find use in organic chemistry. Like many of the lanthanides, the trifluoromethansulfonate, or triflate, of scandium finds use as a so-called Lewis acid, accepting a pair of electrons from a suitable organic molecule, and activating the organic molecule to take part in highly efficient and selective chemical reactions. Scandium is also the source of artificial natural light. This might sound like a contradiction, but when scandium iodide is added in very small amounts to mercury vapour lamps, it produces light that is very similar to natural sunlight, and these lamps are used for applications ranging from floodlights to film projectors. 

Scandium is added in small amounts to aluminium, to produce an alloy which is very light, yet very strong. As such, it has found use as a material for high performance road and mountain bikes. The advent of new frame materials, such as carbon fibre and titanium, has somewhat lessened the popularity of scandium alloy bike frames, but many such frames are still being made today. 

So, that's Scandium - the element first found in the late eighteenth century, and not isolated pure and in large quantities until the middle of the twentieth century. One which helped demonstrate the power of the periodic table, and which you'll find illuminating football fields, and in the frames of mountain bikes. 

Meera Senthilingam   

And bringing us into the light there, was Reading University's David Lindsay, with the bright, strong chemistry of scandium. Now next week an element providing one more punch in the fight to protect our environment. 

Simon Cotton

As everyone knows chlorofluorocarbons, CFCs for short, have been widely used in the past for fridges and freezers as the refridgerant gas. CFCs contribute to both depleting the ozone layer and they are also greenhouse gases. Due to this their use in the developed world has largely ceased, meaning a good, environmentally friendly replacement is needed. Gadolinium may prove useful to the fridges of the future due to a process known as magnetic refridgeration or adiabatic demagnetisation.

Meera Senthilingam     

And join Uppingham School's Simon Cotton, to find out how magnetic refridgeration using the ions of gadolinium will be keeping our food cool in the future, in next week's chemistry in its element. Until then, I'm Meera Senthilingam and thank you for listening.

(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. 

(End promo) 

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Resources

Description :
Assessment for Learning is an effective way of actively involving students in their learning. This is a series of plans based around chemistry topics.
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When concentrated hydrochloric acid is added to a very dilute solution of copper sulfate, the pale blue solution slowly turns yellow-green on the formation of a copper chloride complex. When concentr...
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The purpose of this experiment is to observe and interpret some of the chemistry of three first row transition elements and to compare them with a typical s-block element.
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The Periodic Table allows chemists to see similarities and trends in the properties of chemical elements. This experiment illustrates some properties of the common transition elements and their compo...
Description :
In this experiment you will be looking at a group of transition elements chromium, molybdenum and tungsten.
Description :
The purpose of this experiment is to examine some of the solution chemistry of the transition 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.