Electron density in the sodium vanadium oxide bronze beta-Na(x)V(2)O(5) at 9 K.

ABSTRACT

The crystal structure and electron density in sodium vanadium oxide bronze, beta-Na(x)V(2)O(5) [x = 0.282 (3)], have been studied by accurate Mo Kalpha X-ray diffraction measurements at 9.6 (3) K. No noticeable difference in the crystal structures at room temperature and 9.6 K has been observed. No superstructure reflections, previously found by Kanai, Kagoshima & Nagasawa [(1982), J. Phys. Soc. Jpn, 51, 697-698], have been detected at low temperature. Analysis of the deformation electron density has revealed the presence of the quasi-two-dimensional sheets of the -V-O-V-O- bonds in the structure. The electron density in the different chemical bonds within each of the three crystallographically independent VO(6) polyhedra noticeably varies, although there is no clear evidence that the three crystallographically independent V atoms have different valence states.