The growth units and hydrothermal preparation of lead tungstate (PbWO4) crystallites

The crystal structure of lead tungstate (PbWO4) can be regarded as ordered combination of the tungsten oxide tetrahedrons (WO4) and lead ions (Pb2+). According to the growth unit model, the growth units of lead tungstate are the aggregations of the tungsten oxide tetrahedrons and lead cations with v arious geometry configurations. It is suggested that the favorable growth u nits of lead tungstate crystal are pyramidal, tetragonal prism and quadrang ular units corresponding to geometric orientations of the simple forms of t he crystal. Under low restricted growth conditions, the growth form of lead tungstate crystallites is the aggregation of the geometric configurations of these favorable growth units. The above conclusions are completely confi rmed by the experiment on hydrothermal preparation of lead tungstate crysta llites.