Abstract
Complex ortohoborates of rare earth metals with the general chemical formula R x La 1−x Sc 3 (BO 3 ) 4 (R = Sm, Tb) have been obtained by solid state synthesis and spontaneous crystallization. These crystals belong to the huntite family with the space group R32 and for x = 0.5 have unit cell parameters a = 9.823(6), c = 7.975(3) (SLSB) and a = 9.803(3), c = 7.960(4) Å (TLSB).