Scandium

Scandium, ₂₁Sc
Scandium
Pronunciation	/ˈskændiəm/ (SKAN-dee-əm)
Appearance	silvery white
Standard atomic weight Ar°(Sc)
	44.955907±0.000004; 44.956±0.001 (abridged);
Scandium in the periodic table
	calcium ← scandium → titanium
Atomic number (Z)	21
Group	group 3
Period	period 4
Block	d-block
Electron configuration	[Ar] 3d1 4s2
Electrons per shell	2, 8, 9, 2
Physical properties
Phase at STP	solid
Melting point	1814 K (1541 °C, 2806 °F)
Boiling point	3109 K (2836 °C, 5136 °F)
Density (near r.t.)	2.985 g/cm3
when liquid (at m.p.)	2.80 g/cm3
Heat of fusion	14.1 kJ/mol
Heat of vaporization	332.7 kJ/mol
Molar heat capacity	25.52 J/(mol·K)
Atomic properties
Oxidation states	0, +1, +2, +3 (an amphoteric oxide)
Electronegativity	Pauling scale: 1.36
Ionization energies	1st: 633.1 kJ/mol ; 2nd: 1235.0 kJ/mol ; 3rd: 2388.6 kJ/mol ; (more) ;
Atomic radius	empirical: 162 pm
Covalent radius	170±7 pm
Van der Waals radius	211 pm
	Spectral lines of scandium
Other properties
Natural occurrence	primordial
Crystal structure	hexagonal close-packed (hcp) (hP2)
Lattice constants	a = 330.89 pm c = 526.80 pm (at 20 °C)
Thermal expansion	α, poly: 10.2 µm/(m⋅K) (at r.t.)
Thermal conductivity	15.8 W/(m⋅K)
Electrical resistivity	α, poly: 562 nΩ⋅m (at r.t., calculated)
Magnetic ordering	paramagnetic
Molar magnetic susceptibility	+315.0×10−6 cm3/mol (292 K)
Young's modulus	74.4 GPa
Shear modulus	29.1 GPa
Bulk modulus	56.6 GPa
Poisson ratio	0.279
Brinell hardness	736–1200 MPa
CAS Number	7440-20-2
History
Naming	after Scandinavia
Prediction	Dmitri Mendeleev (1871)
Discovery and first isolation	Lars Fredrik Nilson (1879)
Isotopes of scandium v; e;
γ	44Sc
ε	44Ca
γ	–
γ	–
γ	–
	Category: Scandium; view; talk; edit; \| references

Scandium is a chemical element; it has symbol Sc and atomic number 21. It is a silvery-white metallic d-block element. Historically, it has been classified as a rare-earth element,^[9] together with yttrium and the lanthanides. It was discovered in 1879 by spectral analysis of the minerals euxenite and gadolinite from Scandinavia.^[10]

Scandium is present in most of the deposits of rare-earth and uranium compounds, but it is extracted from these ores in only a few mines worldwide. Because of the low availability and difficulties in the preparation of metallic scandium, which was first done in 1937, applications for scandium were not developed until the 1970s, when the positive effects of scandium on aluminium alloys were discovered. To this day, its use in such alloys remains its only major application. The global trade of scandium oxide is 15–20 tonnes per year.^[11]

The properties of scandium compounds are intermediate between those of aluminium and yttrium. A diagonal relationship exists between the behavior of magnesium and scandium, just as there is between beryllium and aluminium. In the chemical compounds of the elements in group 3, the predominant oxidation state is +3.

^ "Standard Atomic Weights: Scandium". CIAAW. 2021.
^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
^ Cloke, F. Geoffrey N.; Khan, Karl & Perutz, Robin N. (1991). "η-Arene complexes of scandium(0) and scandium(II)". J. Chem. Soc., Chem. Commun. (19): 1372–1373. doi:10.1039/C39910001372.
^ Smith, R. E. (1973). "Diatomic Hydride and Deuteride Spectra of the Second Row Transition Metals". Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences. 332 (1588): 113–127. Bibcode:1973RSPSA.332..113S. doi:10.1098/rspa.1973.0015. S2CID 96908213.
^ McGuire, Joseph C.; Kempter, Charles P. (1960). "Preparation and Properties of Scandium Dihydride". Journal of Chemical Physics. 33 (5): 1584–1585. Bibcode:1960JChPh..33.1584M. doi:10.1063/1.1731452.
^ Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.
^ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
^ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
^ "IUPAC Recommendations, Nomenclature of Inorganic Chemistry" (PDF). Archived from the original (PDF) on 2008-05-27.
^ Samson, Iain M.; Chassé, Mathieu (2016), "Scandium", in White, William M. (ed.), Encyclopedia of Geochemistry: A Comprehensive Reference Source on the Chemistry of the Earth, Cham: Springer International Publishing, pp. 1–5, doi:10.1007/978-3-319-39193-9_281-1, ISBN 978-3-319-39193-9, retrieved 2023-02-01
^ "Mineral Commodity Summaries 2020" (PDF). US Geological Survey Mineral Commodities Summary 2020. US Geological Survey. Retrieved 10 February 2020.

[1] "Standard Atomic Weights: Scandium". CIAAW. 2021.

[CIAAW2021-2] Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.

[3] Cloke, F. Geoffrey N.; Khan, Karl & Perutz, Robin N. (1991). "η-Arene complexes of scandium(0) and scandium(II)". J. Chem. Soc., Chem. Commun. (19): 1372–1373. doi:10.1039/C39910001372.

[Smith-4] Smith, R. E. (1973). "Diatomic Hydride and Deuteride Spectra of the Second Row Transition Metals". Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences. 332 (1588): 113–127. Bibcode:1973RSPSA.332..113S. doi:10.1098/rspa.1973.0015. S2CID 96908213.

[McGuire-5] McGuire, Joseph C.; Kempter, Charles P. (1960). "Preparation and Properties of Scandium Dihydride". Journal of Chemical Physics. 33 (5): 1584–1585. Bibcode:1960JChPh..33.1584M. doi:10.1063/1.1731452.

[Arblaster_2018-6] Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.

[7] Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.

[NUBASE2020-8] Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.

[9] "IUPAC Recommendations, Nomenclature of Inorganic Chemistry" (PDF). Archived from the original (PDF) on 2008-05-27.

[10] Samson, Iain M.; Chassé, Mathieu (2016), "Scandium", in White, William M. (ed.), Encyclopedia of Geochemistry: A Comprehensive Reference Source on the Chemistry of the Earth, Cham: Springer International Publishing, pp. 1–5, doi:10.1007/978-3-319-39193-9_281-1, ISBN 978-3-319-39193-9, retrieved 2023-02-01

[USGS-11] "Mineral Commodity Summaries 2020" (PDF). US Geological Survey Mineral Commodities Summary 2020. US Geological Survey. Retrieved 10 February 2020.

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