High temperature synthesis and crystal structure of new representatives of the huntite family

Abstract

Abstract Single crystals of REE, Al borates, new and known representatives of huntite family are obtained by annealing of REEBO 3 on Al 2 O 3 surface at 1100°C. Phase identification for REE=Pr, Eu, Tb, Tm, Ho, Yb has been carried out using unit cell parameter determination on single crystals. Crystal structures of C 2/ c (PrAl 3 (BO 3 ) 4 ) and C 2 (EuAl 3 (BO 3 ) 4 ) ‐ two polytypic modifications, previously determined for other REE's have been studied. Formation of one or another polytype in similar thermodynamic conditions is probably dependent on electronic structure of rare earth ion. Crystal field stabilization energy in crystal fields of different symmetry is a possible factor of polytype stability (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)