Electron microscopic study on the structure of an intermediate phase with the composition of BaNiO x (2 < x < 3)
Abstract
Structures of barium-nickel oxides represented by the formulae BaNiO 3 and BaNiO 2 were studied by high-resolution electron microscopy. A new phase of BaNiO x (2 < x < 3) as an intermediate was also observed. From the electron diffraction patterns and high-resolution electron microscope images of an intermediate phase, topotaxial phase relations between BaNiO 3 and BaNiO 2 were deduced as follows: {[001] BaNiO3}/{[001] BaNiO2} and {[100] BaNiO3}/{[1 overline10] BaNiO2}. By in situ observation of phase transformation of BaNiO 3 with beam irradiation in electron microscopy, the formation of an intermediate phase of BaNiO x having a superstructure could be confirmed through a series of high-resolution electron microscopic images. The new phase of BaNiO x was found to have an orthorhombic unit cell represented by a superstructure of BaNiO 2 with a0 = 3 a, b0 = b, c0 = 2 c or of BaNiO 3 with a0 = 3 a, c0 = 2 c with the composition ranging between BaNiO 2.33 and BaNiO 2.67.
- Publication:
-
Journal of Solid State Chemistry France
- Pub Date:
- July 1987
- DOI:
- 10.1016/0022-4596(87)90013-2
- Bibcode:
- 1987JSSCh..69...81S