The BaO-B2O3-Na2O ternary system is of great importance for growing crystals of low-temperature modification of barium borate (beta-BaB2O4). A new solid-state triangulation scheme was suggested based on the existence of NaBaBO3 compound. Primary crystallization areas of NaBaBO3 and two new compounds-NaBa4(BO3)(3) and Ba5B4O11-were determined. It was shown that crystals grown from depleted sodium system BaB2O4 NaBaBO3 have great advantage concerning the quality. (C) 2007 Elsevier B.V. All rights reserved.