Sodium tris(carbonato)cobalt(III) is the inorganic compound with the formula NaCo(CO)•3HO.  The salt contains an olive-green metastable cobalt(III) coordination complex.  The salt, a homoleptic metal carbonato complex, is sometimes referred to as the “Field-Durrant precursor” and is prepared by the  “Field-Durrant synthesis”. It is used in the synthesis of other cobalt(III) complexes.  Otherwise cobalt(III) complexes are generated from cobalt(II) precursors, a process that requires an oxidant.