A Raman-scattering study of the vibrational modes in a BiB3O6 crystal was conducted at room temperature. The numbers of external and internal modes obtained in experiment are consistent with the results of a group theoretical analysis. The Raman lines below, 300cm-1 and from, 300 to 1600cm-1 are assigned to the external modes of the lattice and internal vibrations of the BO3 and BO4 subunits of the BiB3O6 structure, respectively.

The growth defects in Nd: YCa4O (BO3) 3 (Nd:YCOB) crystals were investigated by transmission synchrotron topography. It was found that growth striations were the primary defects in Nd: YCOB crystals. Grown-in dislocations, mosaic blocks and inclusions were also observed in the crystals. The effect of temperature field on the formation of growth defects in the crystals was discussed.