The structure of the alpha-phase of bismuth vanadate Bi2VO5.5 has been
determined using single crystal X-ray diffraction data in the space g
roup Aba2. The refinement involves a well defined disorder at the vana
dium site, which incorporates the features of the superlattice structu
re with vanadium tetrahedra and oxygen-deficient octahedra that is dis
placed about the twofold axis. (C) 1997 Elsevier Science Ltd.