High-Pressure Synthesis and Crystal Structure of a New Strontium Ruthenium Oxide: Sr2Ru3O10

The new ternary oxide Sr2Ru3O10has been prepared under hydrothermal conditions (480650°C, 1800-2100 bars) and characterized by X-ray single crystal diffraction data. The structure was refined inC2/mspace group witha=10.985(3) ?,b= 5.635(1) ?,c=6.452(6) ?, and beta=105.3(4)°. The structure refinement converged toR=0.032 andRw=0.042. The ruthenium atoms with a mean oxidation number of 5.33 occupy two sorts of octahedral sites. The first form infinite rutile-like chains parallel to thebaxis, while the second link these chains together to form layers parallel to (100) plane. The average Ru-O bond distance in the two types of octahedra does not allow assignment of an integral oxidation number to individual Ru ions. The Sr2+cations are located in the interlayer space ensuring the stacking cohesion. The Sr2Ru3O10structure can also be described by the stacking of SrO5layers. The same stoichiometry is encountered in the barium fluorides Ba2M3F10(M=Ni, Cu, or Zn) but the stacking sequence is based on BaF3and BaF7layers. Sr2Ru3O10is the first example of strontium ruthenium oxide with Ru/Sr ratio higher than one. The Sr/Ru ratio is allowed by the existence of SrO5layers, which creates 1.5 octahedral sites per SrO5layer.