Preparation and the crystal structure of a new manganate, Sr4Mn3O10

The growth of strontium manganates from melts based on SrCl2SrF2 as solvents yielded orthorhombic crystals of composition Sr4Mn2.964Pt0.036O10 (space group Cmca, a = 5.443(2), b = 12.427(4), c = 12.500(4) Å, Z = 4, ϱcal = 5.34 g cm−3). The platinum incorporated in samples originates from the crucible and may be essential for the crystal stabilization. The structure can be derived from a close-packed arrangement of oxygen and strontium atoms, in which some positions are vacant. This results in a more open structure. Manganese and platinum cations occupy all octahedral voids coordinated by the oxygen atoms only. The characteristic feature of the structure is triple groups of face-shared octahedra which are interconnected by common corners into a two-dimensional framework perpendicular to the [010] direction. Stacking in the third dimension is established by SrO bonds.