Relationship between the Orientations of Tetrahedral [WO_4]~(2-) in Tungstate Crystals and Their Morphology

The relationship between the orientations of tetrahedral [WO4]2- in tungstate crystals withthe scheelite and wolframite structures such as CaWO4 , PbWO4, NaBi(WO4)2, CdWO4, ZnWO4and FeWO4 , which are all the important scintillation materials, and their morphology was studiedfrom the standpoint of crystal chemistry, and the formation mechanisms of their morphology wereanalysed according to the structural orientations of tetrahedral [WO4]2- and the bonding energiesbetween [WO4]2- and metal ions [M2+ ] during growth. It is shown that the morphology oftungstates is related to the orientations of structural units [WO4]2- and [M-O6] or [M-O8] inthese crystals and similar to that of sulfates. The structural features of ABO4 compounds werecompared, and the relationships between structures and growth habits discussed.