Cobalt a structural analog to ferrocene, with cobalt in place of iron. Cobaltocene is much more sensitive to oxidation than ferrocene. Cobalt carbonyl (Co(CO)) is a catalyst in carbonylation and hydrosilylation reactions. Vitamin B (see below) is an organometallic compound found in nature and is the only vitamin that contains a metal atom. An example of an alkylcobalt complex in the otherwise uncommon +4 oxidation state of cobalt is the homoleptic complex (Co(1-norb)), a transition metal-alkyl complex that is notable for its stability to β-hydrogen elimination. The cobalt(III) and cobalt(V) complexes [Li(THF)][Co(1-norb)] and [Co(1-norb)][BF] are also known. Co is the only
Cobalt with water and oxygen to brown cobalt(III) hydroxide (Co(OH)). At temperatures of 600–700 °C, CoO oxidizes to the blue cobalt(II,III) oxide (CoO), which has a spinel structure. Black cobalt(III) oxide (CoO) is also known. Cobalt oxides are antiferromagnetic at low temperature: CoO (Néel temperature 291 K) and CoO (Néel temperature: 40 K), which is analogous to magnetite (FeO), with a mixture of +2 and +3 oxidation states. The principal chalcogenides of cobalt include the black cobalt(II) sulfides, CoS, which adopts a pyrite-like structure, and cobalt(III) sulfide (CoS). Four dihalides of cobalt(II) are known: cobalt(II) fluoride (CoF, pink), cobalt(II) chloride (CoCl,