Element: Scandium
General data
| Element name | Scandium |
|---|---|
| Chemical symbol | Sc |
| Atomic number Z | 21 |
| Year discovered | 1879 |
| Standard state (25°C) | Solid |
| Category | Transition metal |
| Block | d |
| Atomic mass | 44.956 |
| CPK color | #E6E6E6 |
Physical properties
| Melting point | 1814 K (1541 °C) |
|---|---|
| Boiling point | 3109 K (2836 °C) |
| Density | 2.99 g/cm³ |
Energy properties
| First ionization energy | 6.561 eV |
|---|---|
| Electron affinity | 0.188 eV |
Atomic structure
| Protons | 21 (Atomic number) |
|---|---|
| Neutrons (Sc-45, most abundant isotope) | 24 |
| Electrons | 21 |
| Electron configuration | [Ar] 4s² 3d¹ |
| Oxidation states | +3 |
| Electronegativity (Pauling) | 1.36 |
| Atomic radius (van der Waals) | 211 pm |
Ionization energies - NIST ASD (21 states)
| State | Charge | Ioniz. energy (eV) | Type |
|---|---|---|---|
| Sc I | 0+ | 6.56149 ± 0.00006 | measured |
| Sc II | 1+ | 12.79977 ± 0.00025 | measured |
| Sc III | 2+ | 24.756839 ± 0.000012 | measured |
| Sc IV | 3+ | 73.4894 ± 0.0004 | measured |
| Sc V | 4+ | 91.95 ± 0.03 | semi-empirical |
| Sc VI | 5+ | 110.68 ± 0.05 | semi-empirical |
| Sc VII | 6+ | 137.99 ± 0.25 | semi-empirical |
| Sc VIII | 7+ | 158.08 ± 0.25 | semi-empirical |
| Sc IX | 8+ | 180.03 ± 0.12 | measured |
| Sc X | 9+ | 225.18 ± 0.05 | semi-empirical |
| Sc XI | 10+ | 249.798 ± 0.005 | semi-empirical |
| Sc XII | 11+ | 687.36 ± 0.12 | measured |
| Sc XIII | 12+ | 757.7 ± 1 | semi-empirical |
| Sc XIV | 13+ | 833.2 ± 1.4 | semi-empirical |
| Sc XV | 14+ | 926.5 ± 0.7 | semi-empirical |
| Sc XVI | 15+ | 1008.6 ± 0.4 | semi-empirical |
| Sc XVII | 16+ | 1093.5 ± 0.4 | semi-empirical |
| Sc XVIII | 17+ | 1213.1 ± 0.4 | semi-empirical |
| Sc XIX | 18+ | 1287.957 ± 0.007 | calculated |
| Sc XX | 19+ | 5674.9036 ± 0.0004 | calculated |
| Sc XXI | 20+ | 6033.75643 ± 0.00009 | calculated |
Value type as given by NIST ASD: measured - from evaluated experimental data; calculated - from ab initio calculations (mostly highly ionised atoms that have not been measured; for the simplest ones, e.g. H I, the calculation is more accurate than measurement); semi-empirical - from interpolation, extrapolation or another semi-empirical method.
Photos
Isotopes (24)
| A | N | Half-life | Decay |
|---|---|---|---|
| Sc-39 | 18 | unknown | p |
| Sc-40 | 19 | 182.4 ms | EC/β⁺ |
| Sc-41 | 20 | 596.3 ms | EC/β⁺ |
| Sc-42 | 21 | 680.8 ms | EC/β⁺ |
| Sc-43 | 22 | 3.891 h | EC/β⁺ |
| Sc-44 | 23 | 4.0420 h | EC/β⁺ |
| Sc-45 | 24 | stable | - |
| Sc-46 | 25 | 83.81 d | β⁻ |
| Sc-47 | 26 | 3.3491 d | β⁻ |
| Sc-48 | 27 | 43.71 h | β⁻ |
| Sc-49 | 28 | 57.20 min | β⁻ |
| Sc-50 | 29 | 102.5 s | β⁻ |
| Sc-51 | 30 | 12.5 s | β⁻ |
| Sc-52 | 31 | 8.2 s | β⁻ |
| Sc-53 | 32 | 2.4 s | β⁻ |
| Sc-54 | 33 | 526 ms | β⁻ |
| Sc-55 | 34 | 92 ms | β⁻ |
| Sc-56 | 35 | 26 ms | β⁻ |
| Sc-57 | 36 | 20 ms | β⁻ |
| Sc-58 | 37 | 12 ms | β⁻ |
| Sc-59 | 38 | unknown | β⁻ |
| Sc-60 | 39 | unknown | β⁻ |
| Sc-61 | 40 | unknown | β⁻ |
| Sc-62 | 41 | unknown | β⁻ |
Data sources
- PubChem Periodic Table API - Retrieved on 29 June 2026 - licence: CC0
- IUPAC CIAAW - Abridged Standard Atomic Weights 2024 - Table version: 2024 - licence: Public domain
- NNDC Wallet Cards 2023 - Data as of 15 October 2024 - licence: Public domain
- NIST Atomic Spectra Database (ASD) - Retrieved on 29 June 2026 - licence: © U.S. Secretary of Commerce
- Images of Elements - Retrieved on 29 June 2026 - licence: CC BY 3.0