New series of honeycomb ordered oxides, Na3M2SbO6 (M(ii) = Mn, Fe, (Mn, Fe), (Mn, Co)): synthesis, structure and magnetic properties

New members, Na₃M₂SbO₆ (M = Mn, Fe) belonging to the honeycomb family of oxides have been identified through chemical tuning of the oxidation states. The stabilization of Mn²⁺ (d⁵) and Fe²⁺ (d⁶) cations in the honeycomb geometry lead to various magnetic interactions.