Synthesis and characterization of Ca2Bi6V4O21: a new compound in Ca–Bi–V–O system

A new compound in the Ca–Bi–V–O system with the composition Ca2Bi6V4O21 has been prepared and characterized by X-ray diffraction (XRD). Its thermal and electrical properties have also been investigated. The DTA results show the presence of a diffused weak endo in the temperature range 470–550 °C and a sharp endo at 860 °C. The melting temperature of this compound was found to be 890 °C. The XRD study shows that it has a monoclinic unit cell with cell parameters: 11.655(2), 15.295(2), 15.565(2) Å and β=93.70° (1). The electrical conductivities were 3.8×10−4 and 0.7×10−4 Ω−1 cm−1 at 550 and 470 °C, respectively. A highly conducting modification was found to exist above 550 °C.