Oxalate-bridged metal complexes, {NBu4[FeFe(ox)(3)]}(x) (1), {NPr4[FeFe(ox)(3)]}(x) (2), {NPr4[FeCr(ox)(3)]}(x) (3) and Fe-57(II)-doped {NPr4[MnCr(ox)(3)]}(x) (4) were investigated by using Fe-57 Mossbauer spectroscopy, where NBu4+, NPr4+ and ox(2-) are the tetra(n-butyl)ammonium ion, tetra(n-propyl)ammonium ion and oxalate ion, respectively. Magnetically split features of the Mossbauer spectra of 1 and 2 below Neel temperature were similar to each other, while a great difference in magnetization behavior between these compounds was reported. From the temperature dependence of the quadrupole splitting in the paramagnetic states, it was suggested that the axial field splitting of the t(2g) orbitals of Fe(II) is somewhat larger in 1 than in 2. The direction of the internal field at Fe(II) was observed to be approximately parallel in 1-3 and perpendicular in 4 to the honeycomb layers consisting of an alternate array of the bivalent and tervalent metal ions through ox(2-) ligands.