Racemism of trigonal single rare-earth oksiborates

The authors describe the uncovered racemic twinning in single crystals of RM 3(BO 3) 4 (R=Y, La-Lu; M=Fe, Al, Ga) and its dependence on chemical composition of the crystals. The authors prove that number of left and right isomers can be changed by the introduction of substitute elements in R and M sublattices, which makes it possible to eliminate the influence of twinning on the properties of crystals.