Borophosphate crystals of composition Na-5[B2P3O13] (NBP) with dimensions of 50 x 30 x 20 mm(3) have been grown by the Czochralski method. The growth techniques and habit of Na-5[B2P3O13] have been investigated. Difference thermal analysis (DTA), density and infrared (IR) spectrum of Na[B2P3O13] crystals have been measured. These data show that Na-5[B2P3O13] melts congruently at 787degreesC. The crystal is not hygroscopic and has a hardness of 3 Mohs and density is 2.68 g/cm(3). (C) 2003 Elsevier Science B.V. All rights reserved.