A meticulous comparison of crystal structures and vibrational degrees of freedom in the light of A-site substitution for polycrystalline double perovskite oxides A(2)NdSbO(6) (A = Ba, Sr, Ca) has been carried out for accurate identification of crystal symmetry and distortions in these materials. Raman spectra, correlated with group theoretical calculations, characterizes the normal modes of vibrations associated with the oxygen octahedra and establishes a rhombohedral structure for Ba2NdSbO6 and monoclinic structure for Sr2NdSbO6 and Ca2NdSbO6 supporting the X-ray diffraction results. The symmetric stretching mode occurring at the highest frequency is identified as the breathing vibration of the SbO6 octahedra. The frequency and temperature responses of electrical properties studied by impedance spectroscopy show the dominant effect of grain boundaries on the conduction process. The conductivity spectroscopic plots reveal a semiconducting nature. A correlation has been drawn between the vibrational and electrical measurements showing the interplay between the phonon and electronic properties. (C) 2017 Elsevier B.V. All rights reserved.