Choosing systems of ionic radii for crystal-chemical laws in lanthanide oxobromotungstates

The unit cell parameters in LnWO4Br compounds (Ln = La, Pr, Nd, Sm, Eu, Gd, Dy, Er, or Yb) are studied as functions of ionic radii in various systems. The best systems of ionic radii for the description of crystal-chemical laws in lanthanide oxobromotungstates are determined. Crystal-chemical plots are constructed for the unit cell parameters versus lanthanide ionic radius for the specified compounds, as well as the plot of the parameter c for the monoclinic crystal system that accounts for the monoclinic angle β. © 2008 Pleiades Publishing, Ltd.