Cobalt(II) chloride with water
Cobalt(II) chloride without water
Cobalt is a transition metal. It is shiny and conducts electricity. It is magnetic. It is a hard metal. It is moderately reactive. Iron is more reactive and copper is less reactive. It dissolves slowly in acids. This reaction makes hydrogen and a salt of cobalt. Cobalt is normally in its +2 oxidation state as an ion. Some chemical compounds contain cobalt ions in its +4 oxidation state. Cobalt(II) chloride is one of the most common cobalt compounds. Many cobalt compounds are blue or pink. One of them is black.
Cobalt comes in two oxidation states, +2 and +3. Most soluble cobalt compounds are red. They can also be green, blue, brown, and black.
- Cobalt(II) compounds
- Mixed oxidation state
- Cobalt(III) compounds