Эволюция структурных и спектральных характеристик ортоборатов Lu-=SUB=-0.99-x-=/SUB=-Sm-=SUB=-x-=/SUB=-Eu-=SUB=-0.01-=/SUB=-BO-=SUB=-3-=/SUB=-

The structure, IR absorption and luminescence spectra, and morphology of Lu0.99xSmxEu0.01BO3 (0 ≤ x ≤ 0.99) orthoborates synthesized at 970°С were studied. With an increase in the Sm3+ concentration, a successive change of five structural states is observed: calcite (0 ≤ x ≤ 0.1) → calcite + vaterite (0.1 < x < 0.3) → vaterite (0.3 ≤ x ≤ 0.95) → vaterite + a triclinic phase (0.95 < x ≤ 0.98) → a triclinic phase (0.98 < x ≤ 1). A wide range of Sm3+ concentrations at which the vaterite phase (0.3 ≤ x ≤ 0.95) exists and a very narrow region of triclinic phase formation (0.98 < x ≤ 1) are important distinctive features of this system. Correspondence between the structure and spectral characteristics of these compounds was established. It is shown that the vaterite phase appears in the bulk of the microcrystals of the samples that have a calcite structure.