Atomic Properties of Co
- Atomic Number of Co
- 27
- Atomic Mass of Co
- 58.9330 u
- Electron Configuration
- [Ar] 3d7 4s2
- Electronegativity
- 1.88
- Block
- d-block
- Group
- 9
- Period
- 4
Georg Brandt isolated cobalt in the 1730s and showed that brilliant blue pigments in glass came from a distinct metal, not bismuth. Its name traces to kobold, a mining spirit blamed for troublesome ores. The miners' difficulty had a chemical basis: cobalt commonly occurs with nickel, arsenic, sulfur, and other elements that complicate extraction.
Cobalt compounds still produce brilliant blue pigments in ceramics and glass, with exact hue determined by oxidation state and crystal environment. Metallic cobalt is ferromagnetic, and cobalt-containing alloys such as Alnico and samarium-cobalt craft permanent magnets that retain useful properties under demanding conditions. Nickel-based superalloys also use cobalt to tune high-temperature performance.
Modern rechargeable batteries may use cobalt-containing cathode materials to improve energy density and stability. Chemistry and cobalt content vary widely, and manufacturers are reducing or removing it in some designs. Mining and refining, especially where labor and environmental protections are weak, add human consequences to the material story.
Biology uses cobalt at the center of vitamin B12; that does not make arbitrary cobalt salts healthy supplements. Cobalt-60 is a radioactive isotope used in sterilization, industrial radiography, and some radiation therapy, entirely separate from stable cobalt in alloys or vitamins.
This Forger leaves bold marks only when its form is named. A Co ion colors a lattice, an alloy holds magnetization, a cathode exchanges ions, and a sealed radioisotope emits gamma rays. Responsible craftsmanship includes the workers and landscapes behind every blue, battery, and blade.