Synthesis by two methods and crystal structure determination of a new pyrochlore-related compound Sm 2FeTaO 7 Article uri icon

abstract

  • This paper reports on the synthesis of a new pyrochlore-related compound Sm 2FeTaO 7 by both solid state reaction and sol-gel synthesis routes. Structural features were determined by X-ray powder diffraction and Rietveld refinement and were corroborated using Transmission Electron Microscopy (TEM). The results revealed that Sm 2FeTaO 7 crystallized in the monoclinic system with space group C2/c and the following cell parameters: a = 13.1307(5) , b = 7.5854(3) , c = 11.6425(4) and β = 100.971(2)°. The monoclinic structure of Sm 2FeTaO 7 showed an arrangement of alternating SmO and Fe/TaO layers and two types of irregular octahedra of Fe/TaO, which are interconnected into a hexagonal tungsten bronze (HTB)-type network. On the other hand, Sm 2FeTaO 7 prepared by sol-gel was obtained with lower particle sizes than the solid state produced compound. The difference in particle size causes a difference of one order of magnitude in the specific surface area. In addition, energy band gap (E g) of Sm 2FeTaO 7 has a low value of around 2.0 eV. © 2012 Elsevier B.V. All rights reserved.

publication date

  • 2012-01-01