High-pressure synthesis and crystal structure of a new strontium rutheniumoxide: Sr2Ru3O10

The new ternary oxide Sr2Ru3O10 has been prepared under hydrothermal condit ions (480-650 degrees C, 1800-2100 bars) and characterized by X-ray single crystal diffraction data. The structure was refined in C2/m space group wit h a 10.985(3) Angstrom, b = 5.635(1) Angstrom, c = 6.452(6) Angstrom, and b eta = 105,3(4)degrees, The structure refinement converged to R = 0.032 and R-w = 0.042, The ruthenium atoms with a mean oxidation number of 5.33 occup y two sorts of octahedral sites, The first form infinite rutile-like chains parallel to the b axis, while the second link these chains together to for m 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 numb er to individual Ru ions. The Sr2+ cations are located in the interlayer sp ace ensuring the stacking cohesion. The Sr2Ru3O10 structure can also be des cribed by the stacking of SrO5 layers, The same stoichiometry is encountere d in the barium fluorides Ba2M3F10 (M= Ni, Cu, or Zn) but the stacking sequ ence is based on BaF3 and BaF7 layers. Sr2Ru3O10 is the first example of st rontium ruthenium oxide with Ru/Sr ratio higher than one. The Sr/Ru ratio i s allowed by the existence of SrO5 layers, which creates 1.5 octahedral sit es per SrO5 layer. (C) 1999 Academic Press.