Das erste oxidische T5‐Supertetraeder: Na26Mn39O55

The First T5‐Supertetrahedron in Oxide Chemistry: Na₂₆Mn₃₉O₅₅ Na₂₆Mn₃₉O₅₅ has been obtained from a redox reaction between manganese metal, CdO in the presence of Na₂O and Na₂SO₄ as a flux component as red single crystals with octahedral shape. The crystal structure has been determined from single crystal data (Fd3¯m, Z = 8, a = 2377.4(3) pm at 293 K and a = 2372.5(2) pm at 130 K). The rare characteristic structural feature of a T5‐Supertetrahedron, [Mn₃₅O₅₆], is observed for this new mixed‐valent sodium‐oxomanganat(II, III), Na₂₆Mn₃₉O₅₅. First investigations of the magnetic properties are reported.