Thermal variation of structure and electrical conductivity in Bi14WO24
Anna Borowska-Centkowska , Franciszek Krok , I. Abrahams , Wojciech Wróbel , J.R. Dygas , S. Hull
AbstractStructure and electrical conductivity of Bi14WO24 as a function of temperature have been examined by X-ray and neutron powder diffraction, a.c. impedance spectroscopy and differential thermal analysis. The room temperature structure was successfully refined using a monoclinic subcell model in space group I2/m. However, additional reflections in the neutron data are consistent with a large supercell of dimensions a = 17.3780(1) Å, b = 17.3891(1) Å, c = 26.1785(2) Å and β = 90.270(1)°, as previously proposed. Transitions to tetragonal and cubic phases are observed at ca. 35 °C and 780 °C, respectively. The structure of the high temperature polymorph is confirmed as a fully disordered δ-Bi2O3 type phase. Analysis of the defect structure is consistent with a predominantly tetrahedral environment for tungsten, as seen at low temperatures. The conductivity behaviour is correlated with the appearance of the δ-phase at high temperatures and exhibits a value of 0.97 S cm− 1 at 800 °C.
|Journal series||Solid State Ionics, ISSN 0167-2738, (A 35 pkt)|
|Keywords in English||Bismuth oxide, Bismuth tungsten oxide, Defect structure, Fluorite, impedance spectroscopy, Neutron diffraction|
|ASJC Classification||; ;|
|Publication indicators||= 4; = 5; = 1.0; : 2011 = 1.615; : 2011 = 2.646 (2) - 2011=3.097 (5)|
|Citation count*||1 (2015-05-11)|
* presented citation count is obtained through Internet information analysis and it is close to the number calculated by the Publish or Perish system.