Phonon spectra of recently synthesized Ag(II)SO4 have been measured using infrared absorption and Raman scattering spectroscopy, and theoretically predicted using density functional theory calculations. Excellent agreement between experimental and theoretical results with correlation coefficient of 1.05 allowed for full assignment of the experimentally observed vibrational bands, as well as calculation of standard vibrational entropy of AgSO4 (118.2Jmol−1K−1), vibrational heat capacity at constant volume (99.1Jmol−1K−1), zero-point energy (48.3kJmol−1). The experimental cut-off frequency of the phonon spectrum equals 1116cm−1 which translates to the Debye temperature of 1606K. High frequencies of S–O stretching modes render sulfate connections of Ag(II) attractive precursors of high-TC superconductors.