| Discovery date | 1879 |
| Discovered by | Lars Frederik Nilson |
| Origin of the name | The name derives from 'Scandia', the Latin name for Scandinavia. |
| Allotropes |
|
Sc
Scandium
21
44.956
| Group | 3 | Melting point | 1541°C, 2806°F, 1814 K |
| Period | 4 | Boiling point | 2836°C, 5137°F, 3109 K |
| Block | d | Density (g cm−3) | 2.99 |
| Atomic number | 21 | Relative atomic mass | 44.956 |
| State at 20°C | Solid | Key isotopes | 45Sc |
| Electron configuration | [Ar] 3d14s2 | CAS number | 7440-20-2 |
| ChemSpider ID | 22392 | ChemSpider is a free chemical structure database | |
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.
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.
| Atomic radius, non-bonded (Å) | 2.15 | Covalent radius (Å) | 1.59 |
| Electron affinity (kJ mol−1) | 18.139 |
Electronegativity (Pauling scale) |
1.36 |
|
Ionisation energies (kJ mol−1) |
1st
633.088
2nd
1234.99
3rd
2388.655
4th
7090.65
5th
8842.88
6th
10679
7th
13315
8th
15254.3
|
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| Common oxidation states | 3 | ||||
| Isotopes | Isotope | Atomic mass | Natural abundance (%) | Half life | Mode of decay |
| 45Sc | 44.956 | 100 | - | - | |
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Specific heat capacity (J kg−1 K−1) |
568 | Young's modulus (GPa) | 74.4 | |||||||||||
| Shear modulus (GPa) | 29.1 | Bulk modulus (GPa) | 56.6 | |||||||||||
| Vapour pressure | ||||||||||||||
| Temperature (K) |
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| Pressure (Pa) |
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| Listen to Scandium Podcast |
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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.com. There's more information and other episodes of Chemistry in its element on our website at chemistryworld.org/elements. (End promo)
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Visual Elements images and videos
© Murray Robertson 1998-2017.
W. M. Haynes, ed., CRC Handbook of Chemistry and Physics, CRC Press/Taylor and Francis, Boca Raton, FL, 95th Edition, Internet Version 2015, accessed December 2014.
Tables of Physical & Chemical Constants, Kaye & Laby Online, 16th edition, 1995. Version 1.0 (2005), accessed December 2014.
J. S. Coursey, D. J. Schwab, J. J. Tsai, and R. A. Dragoset, Atomic Weights and Isotopic Compositions (version 4.1), 2015, National Institute of Standards and Technology, Gaithersburg, MD, accessed November 2016.
T. L. Cottrell, The Strengths of Chemical Bonds, Butterworth, London, 1954.
John Emsley, Nature’s Building Blocks: An A-Z Guide to the Elements, Oxford University Press, New York, 2nd Edition, 2011.
Thomas Jefferson National Accelerator Facility - Office of Science Education, It’s Elemental - The Periodic Table of Elements, accessed December 2014.
Periodic Table of Videos, accessed December 2014.
Derived in part from material provided by the British Geological Survey © NERC.
Elements 1-112, 114, 116 and 117 © John Emsley 2012. Elements 113, 115, 117 and 118 © Royal Society of Chemistry 2017.
Produced by The Naked Scientists.
Created by video journalist Brady Haran working with chemists at The University of Nottingham.
© Murray Robertson 1998-2017.
Data
W. M. Haynes, ed., CRC Handbook of Chemistry and Physics, CRC Press/Taylor and Francis, Boca Raton, FL, 95th Edition, Internet Version 2015, accessed December 2014.
Tables of Physical & Chemical Constants, Kaye & Laby Online, 16th edition, 1995. Version 1.0 (2005), accessed December 2014.
J. S. Coursey, D. J. Schwab, J. J. Tsai, and R. A. Dragoset, Atomic Weights and Isotopic Compositions (version 4.1), 2015, National Institute of Standards and Technology, Gaithersburg, MD, accessed November 2016.
T. L. Cottrell, The Strengths of Chemical Bonds, Butterworth, London, 1954.
Uses and properties
John Emsley, Nature’s Building Blocks: An A-Z Guide to the Elements, Oxford University Press, New York, 2nd Edition, 2011.
Thomas Jefferson National Accelerator Facility - Office of Science Education, It’s Elemental - The Periodic Table of Elements, accessed December 2014.
Periodic Table of Videos, accessed December 2014.
Supply risk data
Derived in part from material provided by the British Geological Survey © NERC.
History text
Elements 1-112, 114, 116 and 117 © John Emsley 2012. Elements 113, 115, 117 and 118 © Royal Society of Chemistry 2017.
Podcasts
Produced by The Naked Scientists.
Periodic Table of Videos
Created by video journalist Brady Haran working with chemists at The University of Nottingham.
