In this work, bar- and disk-shaped resonators were fabricated using Al(0.8)4Sc(0.16)N thin film Sensitivity analysis of the resonators' resonance frequencies with respect to the piezoelectric material parameters revealed that resonance analysis can be used for material parameter extraction. An optimization algorithm is employed to determine the piezoelectric material parameters S-11(E), s(12)(E), and d(31) of Al0.84Sc0.16N from the length- and radial-extensional mode. Using the piezoelectric constitutive equations and combining the results obtained in this work with the results obtained in a previous work, the stress-charge form of elastic and piezoelectric parameters could be derived.