aState Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, P. R. China
bCollege of Material and Chemistry, Changchun University of Science and Technology, Changchun 130022, P. R. China
Corresponding author. Tel./fax: +86 431 85168346.
Received 8 November 2012
Revised 27 January 2013
Accepted 29 January 2013
Available online 8 February 2013
Abstract
The Raman and synchrotron angle-dispersive X-ray diffraction studies have been performed on NaBi(WO4)2 under high pressure up to 30.7 and 36.2 GPa, respectively, at room temperature. With pressure increases to ∼7.0 GPa, the structure of NaBi(WO4)2 begins to transform from tetragonal (I41/a) into monoclinic (P2/m), and the phase transition completes around 13 GPa. With pressure higher than 29.0 GPa, the NaBi(WO4)2 turns into amorphous state. The random arrangement of Na+ and Bi3+ in short-range ordered scheelite NaBi(WO4)2 results in the tetragonal to monoclinic phase transition, which is different from that observed in AWO4 tungstates and AMoO4 molybdates (A=Ca, Sr, Ba, Pb, Eu, Cd).
