Synthesis and Characterization of New Composite Oxides Related to the 2H-Perovskite Structure Type

1998 ◽  
Vol 547 ◽  
Author(s):  
J. B. Claridge ◽  
H.-C. zur Loye

AbstractThe synthesis, structural characterization, and magnetic properties of three strontium rhodium oxides Sr6Rh5O15, Sr4Rh3O9+δ, and Sr9Rh7O21+δ, is presented. While Sr6Rh5O15 is an example of a commensurate n = 1 member of the A3n+3A'nBn+3O6n+9 family of oxides, Sr4Rh3O9+δ, and Sr9Rh7O21+°, are examples of incommensurate n =2 and n = 3 members. Sr6Rh5O15 crystallizes in space group R32, a = 19.3197(2) Å, c = 13.0418(1) Å. The Sr6Rh5O15 structure is a superstructure of the Ba6Ni5O15 structure type. Sr4Rh3O9+δ, and Sr9Rh7P21+δ crystallize in the superspace group with lattice parameters of a = 9.6007(6), c1 = 2.6881(2), c2 = 4.2373(3), and a = 9.6127(6), c1 = 2.6769(2), c2 = 4.252(1), respectively. Their magnetic data are consistent with antiferromagnetic coupling between the chains leading to an ordered state at low temperature.

2002 ◽  
Vol 718 ◽  
Author(s):  
Job Rijssenbeek ◽  
Sylvie Malo ◽  
Takashi Saito ◽  
Vincent Caignaert ◽  
Masaki Azuma ◽  
...  

AbstractPerovskite-like mixed metal ruthenates are of interest owing to their varied electronic and magnetic properties, which are heavily dependent on the ordering of the transition metals. We report the synthesis and structural characterization of the first 1:2 ordered perovskite ruthenate, Sr3CaRu2O9. The structure was determined from a combination of powder X-ray, electron and neutron diffraction data and is characterized by a 1:2 ordering of Ca2+ and Ru5+ over the sixcoordinate B-sites of the perovskite lattice. Sr3CaRu2O9 is the first example of this structure-type to include a majority metal with d electrons (Ru(V), d3). The relationship of this material to the K2NiF4-type Sr1.5Ca0.5RuO4 (i.e., Sr3CaRu2O8) highlights the dramatic effects of the ruthenium valence on the resultant structure. Remarkably, these two structures can be quantitatively interconverted by the appropriate choice of reaction temperature and atmosphere.


2007 ◽  
Vol 5 (1) ◽  
pp. 169-176 ◽  
Author(s):  
Abdülhadi Baykal ◽  
Yüksel Köseoğlu ◽  
Mehmet Şenel

AbstractHeating hydrous manganese (II) hydroxide gel at 85 °C for 12 hours produces Mn3O4 nanoparticles. They were characterized by X-ray powder diffraction (XRD) and infrared spectroscopy (FTIR). The particle size estimated from the SEM and X-ray peak broadening is approximately 32 nm, showing them to be nanocrystalline. EPR measurements confirm a typical Mn2+signal with a highly resolved hyperfine structure.


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