27Co58.93319
Cobalt
Transition Metal
Solid at STP
Period 4Group 9Block DDiscovered 1735
[Ar]4s2 3d7
Cobalt is a chemical element with symbol Co and atomic number 27. Like nickel, cobalt in the Earth's crust is found only in chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal.
📖 Read more on Wikipedia →Atomic Properties
| Atomic Number | 27 |
| Atomic Mass | 58.93319 u |
| Electron Configuration | [Ar]4s2 3d7 |
| Oxidation States | +3, +2 |
| Electronegativity | 1.88 (Pauling) |
| Atomic Radius | 192 pm |
| Ionization Energy | 7.881 eV |
| Electron Affinity | 0.661 eV |
| Block | D |
Physical Properties
| Appearance | hard lustrous gray metal |
| Standard State | Solid |
| Melting Point | 1768 K (1494.8 °C) |
| Boiling Point | 3200 K (2926.8 °C) |
| Density | 8.86 g/cm³ |
| Molar Heat | 24.81 J/(mol·K) |
| CPK Color | #F090A0 |
Classification
| Category | Transition Metal |
| Group Block | Transition metal |
| Period | 4 |
| Group | 9 |
| Block | D |
Discovery
| Year Discovered | 1735 |
| Discovered By | Georg Brandt |
| Electron Shells | 2, 8, 15, 2 |