Scandium
transition metal · period 4 · group 3 · d-block
Scandium is a chemical element with the symbol Sc and atomic number 21. A silvery-white metallic d-block element, it has historically been classified as a rare-earth element, together with yttrium and the lanthanides. It was discovered in 1879 by spectral analysis of the minerals euxenite and gadolinite from Scandinavia. 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.
What the numbers say
At standard temperature and pressure Scandium is a solid, sitting in period 4, group 3 of the d-block.
Its melting point of 1814 K (1541 °C) is the 26th highest of the 110 elements with a measured value — mid-range among the elements.
At 2.985 g/cm³ it is the 70th densest of 96 elements with a quoted density.
Pauling electronegativity is 1.36. Paired with oxygen (3.44) that is a difference of 2.08, which puts the bond predominantly ionic — expect a stable oxide ceramic.
In the solid state it takes a simple hexagonal structure — hexagonal packing offers few easy slip systems, so properties are anisotropic and formability is limited.
It is reported in 3 oxidation states (1, 2, 3), which sets how many distinct compounds and phases it can form.
First identified in 1879.
Crystal structure
Solid Scandium adopts a Simple Hexagonal arrangement, in the Hexagonal system — axes a = b ≠ c, angles α = β = 90°, γ = 120°. Symmetry controls the anisotropy of stiffness and thermal expansion, and the available slip systems set how far the metal deforms before it fractures.
Check it against computed structures
The structure search queries the Materials Project, OQMD and the Open Materials Database for computed crystal structures containing Sc — with DFT formation energy, hull stability and band gap where the provider publishes them.
K 2 · L 8 · M 9 · N 2
Properties
| Atomic number | 21 |
|---|---|
| Atomic mass | 44.9559085 u |
| Series | transition metal |
| Group | 3 |
| Period | 4 |
| Block | d-block |
| Phase at STP | Solid |
| Density | 2.985 g/cm³ |
| Melting point | 1814 K (1541 °C) |
| Boiling point | 3109 K (2836 °C) |
| Electronegativity (Pauling) | 1.36 |
| Electron configuration | [Ar] 3d¹ 4s² |
| Crystal structure | Simple Hexagonal |
| Oxidation states | 1,2,3 |
| Discovered | 1879 |
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See Sc in context with all 118 elements.
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