Powder Diffraction

Table of Contents - March 2011 - Volume 26, Issue 01  

Technical Articles

Crystal structure of layered perovskite compound, Li2LaTa2O6N

Motoaki Kagaa1, Hirokazu Kurachia1, Toru Asakaa1, Bing Yuea2a3, Jinhua Yea2a3 and Koichiro Fukudaa1 c1

a1 Department of Environmental and Materials Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan

a2 Photocatalytic Material Center, National Institute for Materials Science (NIMS), Ibaraki 305-0047, Japan

a3 Department of Chemistry, Graduate School of Science, Hokaido University, Sapporo 060–0808, Japan

Abstract

The crystal structure of Li2LaTa2O6N was determined from laboratory X-ray powder diffraction data (Cu Kα1) using the Rietveld method. The title compound is tetragonal with space group I4/mmm, Z=2, and unit-cell dimensions a=0.395 049(4) nm, c=1.850 97(3) nm, and V=0.288 869(6) nm3. The initial structural model was successfully derived by the direct methods and further refined by the Rietveld method, with the anisotropic atomic displacement parameters being assigned for all atoms. The final reliability indices were Rwp=5.73%, S=1.46, Rp=4.33%, RB=1.13%, and RF=0.53%. Li2LaTa2O6N has a layered perovskite structure similar to that of Li2LaTa2O7.

(Received October 04 2010)

(Accepted November 30 2010)

Key words

  • oxynitride;
  • layered perovskite;
  • X-ray powder diffraction;
  • Rietveld method;
  • photocatalyst

Correspondence:

c1 Author to whom correspondence should be addressed. Electronic mail: fukuda.koichiro@nitech.ac.jp