Scandium

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Scandium
21Sc
-

Sc

Y
calciumscandiumtitanium
Appearance
silvery white
General properties
Name, seembol, nummer scandium, Sc, 21
Pronunciation /ˈskændiəm/ SKAN-dee-əm
Element category transeetion metal
Group, period, block 3, 4, d
Staundart atomic wicht 44.955912(6)
Electron confeeguration [Ar] 3d1 4s2
2, 8, 9, 2
Electron shells of scandium (2, 8, 9, 2)
History
Namin efter Scandinavie
Prediction Dmitri Mendeleev (1871)
Discovery Lars Fredrik Nilson (1879)
First isolation Lars Fredrik Nilson (1879)
Physical properties
Phase solid
Density (near r.t.) 2.985 g·cm−3
Liquid density at m.p. 2.80 g·cm−3
Meltin pynt 1814 K, 1541 °C, 2806 °F
Boilin pynt 3109 K, 2836 °C, 5136 °F
Heat o fusion 14.1 kJ·mol−1
Heat o vaporization 332.7 kJ·mol−1
Molar heat capacity 25.52 J·mol−1·K−1
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 1645 1804 (2006) (2266) (2613) (3101)
Atomic properties
Oxidation states 3, 2[1], 1[2]
(amphoteric oxide)
Electronegativity 1.36 (Pauling scale)
Ionization energies
(more)
1st: 633.1 kJ·mol−1
2nt: 1235.0 kJ·mol−1
3rd: 2388.6 kJ·mol−1
Atomic radius 162 pm
Covalent radius 170±7 pm
Van der Waals radius 211 pm
Miscellanea
Crystal structure hexagonal close-packed
Scandium has a hexagonal close packed crystal structure
Magnetic orderin paramagnetic
Electrical resistivity (r.t.) (α, poly)
calc. 562 nΩ·m
Thermal conductivity 15.8 W·m−1·K−1
Thermal expansion (r.t.) (α, poly)
10.2 µm/(m·K)
Young's modulus 74.4 GPa
Shear modulus 29.1 GPa
Bulk modulus 56.6 GPa
Poisson ratio 0.279
Brinell hairdness 750 MPa
CAS registry nummer 7440-20-2
Most stable isotopes
Main article: Isotopes o scandium
iso NA hauf-life DM DE (MeV) DP
44m2Sc syn 58.61 h IT 0.2709 44Sc
γ 1.0, 1.1, 1.1 44Sc
ε - 44Ca
45Sc 100% 45Sc is stable wi 24 neutrons
46Sc syn 83.79 d β 0.3569 46Ti
γ 0.889, 1.120 -
47Sc syn 3.3492 d β 0.44, 0.60 47Ti
γ 0.159 -
48Sc syn 43.67 h β 0.661 48Ti
γ 0.9, 1.3, 1.0 -
· r

Scandium is a chemical element wi seembol Sc an atomic nummer 21. A sillery-white metallic transeetion metal, it haes historically been sometimes classified as a rare yird element, thegither wi yttrium an the lanthanoids. It wis discovered in 1879 bi spectral analysis o the minerals euxenite an gadolinite frae Scandinavie.

Scandium is present in maist o the deposits o rare yird an uranium compoonds, but it is extractit frae these ores in anly a few mines warldwide. Acause o the law availability an the difficulties in the preparation o metallic scandium, which wis first done in 1937, it teuk till the 1970s before applications for scandium wur developed. The positive effects o scandium on aluminium alloys wur discovered in the 1970s, an its uise in such alloys remains its anly major application. The global trade o the pure metal is aroond a hundred poonds a year on average.[3]

The properties o scandium compoonds are intermediate atween those o aluminium an yttrium. A diagonal relationship exists atween the behavior o magnesium an scandium, juist as thare is atween beryllium an aluminium. In the chemical compoonds o the elements shawn as group 3, above, the predominant oxidation state is +3.

References[eedit | eedit soorce]

  1. McGuire, Joseph C.; Kempter, Charles P. (1960). "Preparation and Properties of Scandium Dihydride". Journal of Chemical Physics 33: 1584–1585. Bibcode:1960JChPh..33.1584M. doi:10.1063/1.1731452. 
  2. 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. 
  3. Gray, Theodore (2012) The Elements, Black Dog & Leventhal Publishers, p. 57, ISBN 1579128955.

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