We report inelastic and elastic neutron scattering, magnetic susceptibility, and heat capacity measurements for polycrystalline sodium ruthenate (Na(3)RuO(4)). Previous work suggests that this material consists of isolated tetramers of S = 3/2 Ru(5+) ions in a so-called lozenge configuration. Comparisons of magnetic susceptibility and inelastic and elastic neutron scattering results with analytic calculations for several cluster models show that although there may be significant spin-spin correlations within the lozenge cluster, a simple isolated lozenge model is not appropriate for Na(3)RuO(4).