Über ein neues Oxoferrat mit „Butterfly-Motiv”︁: K2Na4[Fe2O5]

A New Oxoferrate with “Butterfly-Motiv”: K₂Na₄[Fe₂O₅] Dark red-brown single-crystals of K₂Na₄[Fe₂O₅] were obtained for the first time by heating “K₃Na₃CdO₄” at 500°C in closed Fe-cylinders. Determination and refinement of the crystal structure confirms the space group P4₂/mnm (No. 136). Four-circle diffractometer data: MoKα , 373 out of 373 I_o(hkl); R = 5.3%; R_w = 4.6%; a = 645.94(5), c = 1 039.2(1) pm. In contrast to the already known oxoferrates(II) with the “Butterfly-Motiv”, Rb₆[Fe₂O₅] and K₆[Fe₂O₅] [1], we now found an isotypic structure for K₂Na₄[Fe₂O₅] with the oxocobaltates of Rb₂Na₄[Co₂O₅] and K₂Na₄[Co₂O₅] [2].