Boron nitride flakes and hollow spheres were synthesized by coreduction of NH4Cl and BBr3 using sodium as reductant. Xray powder diffraction (XRD) pattern could be indexed as hexagonal BN. The X-ray photoelectron spectra (XPS) were used to determine the composition ratio, which is B:N = 1:1.05. The transmission electron microscopy (TEM) images showed flake-like and hollow spherical morphology.