%0 Journal Article
%T CRYSTAL STRUCTURE AND OPTICAL OBSERVATIONS OF BiV04<br>BiVO4的晶体结构和光学观察
%A LIU JIAN-CHENG
%A CHEN JIA-PING
%A LI DE-YU
%A <br>刘建成
%A 陈家平
%A 李德宇
%J 物理学报
%D 1983
%I 
%X A single-crystal X-ray diffraction analysis has been performed on fergusonite BiVO4 synthesized by pulling method. At room temperature the crystal belongs to monoclinic system, with space group B2/b, z = 4, and cell parameters a = 7.247?, b=5.096?, c = 11.702? and r =134.18o. The structure has been analysed by two and three-dimensional Patterson procedure, and calculated through three-dimensional electron density. A full-matrix, least square refinement gave R=0.067, Rw =0.058 for 335 independent reflections. An absorption and secondary extinction correction gave final R = 0.058. The Bi and V atoms occupy a respective set of 4e special positions and the O atoms two sets of general positions. The oxygen atoms take part in four-fold coordinations around vanadium in the sense that they form regular VO4 tetrahedra. The structure also shows eight-fold oxygen coordinations around bismuth and form distorted Bi-O dodecahedron. The space groups for temperatures above and below Tc are found to be I41/a and 12/b (or B2/b) respectivelv. The phase transition from tetragonal to monoclinic does skip over a possible intermediate orthorhombic modification. The phase transition is apparently driven by a lone-pair distortion of the Bi-O polyhedron. Bi3+ and V5+ displace alternatively up and down along the c axis, resulting in a layer-like Character for monoclinic BiVO4 The character has been proved by optical observations. The BiVO4 crystal cleaves easily to give smooth (cleavage) faces parallel to plane perpendicular to the c axis.Three kinds of samples, i.e crystals with cell-like structure and disc shape, crystal ribbon with natural cleavage and powder crystal grain, were used for optical observation, and the relationship between the transmittance of BiVO4 and optical wave-length was studied.
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=6E709DC38FA1D09A4B578DD0906875B5B44D4D294832BB8E&cid=47EA7CFDDEBB28E0&jid=29DF2CB55EF687E7EFA80DFD4B978260&aid=4562DADE646014E5A1B4F82F7825EA78&yid=A7F20A391020FDEE&vid=9971A5E270697F23&iid=5D311CA918CA9A03&sid=8CE636FB0B122692&eid=6B1D468AD7B8ADD8&journal_id=1000-3290&journal_name=物理学报&referenced_num=0&reference_num=0