Аннотация:Mixed potassium-sodium ferrate(VI), K3Na(FeO4)2 has been synthesised by precipitation from alkaline solution. It crystallise in a hexagonal system with lattice parameters а=5.827±0.002 Å, c=7.542±0.003 Å and belongs to glaserite-like structures (space group P/3m1). Iron is present in oxidation state +6: room temperature Mössbauer spectrum is a doublet with isomer shift = 0.89±0.01 mms-1 (relative to -iron), quadrupole splitting =0.21±0.01 mm/s-1 and full width at half-height =0.22±0.01 mms-1.