Synthesis crystal structure and ionic conductivity of Ca0.5BiV2O10 and Sr0.5Bi3V2O10

Two new compounds Ca0.5Bi3V2O10 and Sr0.5Bi3V2O10 have been synthesized in the ternary system: MO-Bi2O3-V2O5 system (M= M2+). The crystal structure of Sr0.5Bi3V2O10 has been determined from single crystal X-ray diffraction data, space group P (1) over bar and Z=2, with cell parameters a=7.1453(3)Angstrom, b=7.8921(3)Angstrom, c=9.3297(3)Angstrom, alpha=106.444(2)degrees, beta=94.088(2)degrees, gamma=112.445(2)degrees, V=456.72(4) Angstrom(3). Ca0.5Bi3V2O10 is isostructural with Sr0.5Bi3V2O10, with, a=7.0810(2)Angstrom, b=7.8447(2)Angstrom, c=9.3607(2)Angstrom, alpha=106.202(1)degrees, beta=94.572(1)degrees, gamma=112.659(1)degrees, V=450.38(2) Angstrom(3) and its structure has been refined by Rietveld method using powder X-ray data. The crystal structure consists of infinite chains of (Bi2O2) along c-axis formed by linkage of BiO8 and BiO6 polyhedra interconnected by MO8 polyhedra forming 2D layers in ac plane. The vanadate tetrahedra are sandwiched between these layers. Conductivity measurements give a maximum conductivity value of 4.54 x 10(-5) and 3.63 x 10(-5) S cm(-1) for Ca0.5Bi3V2O10 and Sr0.5Bi3V2O10, respectively at 725 degreesC. (C) 2004 Elsevier Inc. All rights reserved.