cobalt ii chromate formula
The cobalt ii chromate formula (CrO4) is a solid red to pink metallic salt that mixes well with water and is widely used in electrochemical industries, as a dyeing agent, as a supplement for Vitamin B12 deficiency and as a drying agent for paint and ink. It is also a foam stabilizer in some breweries.
It can be separated from nickel and other metals by a complexometric titration with EDTA. It is also used as a color indicator and as an indicator in cation separation.
Several other compounds can be made from this metal, including Co(II), a mixed oxide that is stable to atmospheric oxygen at temperatures above 900 deg C; Co3O4, the most common cobalt compound; and Co60, a radioactive tracer used in radiography. The chemical properties of Co-60 are important in the manufacture of magnetic and high-strength superalloys.
The main oxidation states of cobalt are Co(2 +) and Co(3 +). At normal room temperature, these oxidation states are neutral but when heated, cobalt is oxidized to the mixed oxide Co(II,III) oxide (Co3O4).
When dissolved in acid solution, Co3+ forms octahedral complexes with electron-donor ligands such as ammonia, ethylene-diaminetetraacetic acid and some phthalocyanines. These complexes strongly stabilize Co3+ in solution and are thus more stable than uncomplexed Co2+.
The electrode potentials for the half-reactions involving these complexes depend on the oxidation state of the cobalt and the ligand. As a rule of thumb, the higher the oxidation state, the more unstable the cobalt is in acid solution and the faster it is reduced by the complexing ligand to a stable form.