short communications
The electron diffraction technique was employed to unambiguously clarify the crystal symmetries of ferroelectric Bi4Ti3O12 and Bi3.15Nd0.85Ti3O12 single crystals at room temperature. On the basis of the monoclinic space group B1a1, the lattice parameters of both the ferroelectrics were calculated by the Rietveld refinement of powder X-ray diffraction data.