Cobalamin may refer to several substances depending on the upper axial ligand of the cobalt ion.

In Vitamin B12 a cobalt(II) ion is held in a corrin ring.

The core of the molecule vitamin B (cobalamin) is a corrin structure (depicted in red) with at its center a cobalt ion.

Some chemical compounds contain cobalt ions in its +4 oxidation state.

Dimethylmercury, colorless, extremely toxic liquidCobalt compounds are chemical compounds containing cobalt ions.

It is colored to a deep powder blue hue using cobalt ions derived from cobalt oxide.

DynamiteCobalt compounds are chemical compounds containing cobalt ions.

Paris Green, extremely toxic, bright blue-greenCobalt compounds are chemical compounds containing cobalt ions.

Sodium periodate, white solidCobalt compounds are chemical compounds containing cobalt ions.

Here the cobalt ion has the oxidation state of +2, and it is a d ion.