Cobalt(III) oxide is the

inorganic compound An inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds⁠that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemistry''. Inorgan ...

with the formula of Co₂O₃. Although only two oxides of cobalt are well characterized, CoO and Co₃O₄, procedures claiming to give Co₂O₃ have been described. Thus treatment of Co(II) salts such as cobalt(II) sulfate with an aqueous solution of

sodium hypochlorite Sodium hypochlorite is an alkaline inorganic chemical compound with the formula (also written as NaClO). It is commonly known in a dilute aqueous solution as bleach or chlorine bleach. It is the sodium salt of hypochlorous acid, consisting of ...

(also known as bleach) gives a black solid: :2CoSO₄ + 4NaOH + NaOCl → Co₂O₃ + 2Na₂SO₄ + NaCl Some formulations of the catalyst hopcalite contain "Co₂O₃". Some studies have been unable to synthesize the compound, and report that it is theoretically unstable. It is soluble in cold diluted

sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (English in the Commonwealth of Nations, Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, ...

and produces Co₂ O₄sub>3, which is blue in aqueous solution. : Co₂O₃ + 3H₂SO₄ → Co₂ O₄sub>3 + 3H₂O Cobalt(III) ion is a strong oxidizer in acidic solution, its

standard electrode potential In electrochemistry, standard electrode potential E^\ominus, or E^\ominus_, is the electrode potential (a measure of the reducing power of any element or compound) which the IUPAC "Gold Book" defines as ''"the value of the standard emf ( electrom ...

is +1.84V in this situation.

References

{{oxygen compounds Cobalt(III) compounds Sesquioxides Transition metal oxides

See also

References