The Fe-57 Mossbauer quadrupole splittings (DeltaE(Q)) and isomer shifts (delta(Fe)) in 3-coordinate high-spin Fe(II) complexes are unusually small, and previous attempts to reproduce their DeltaE(Q) values have been unsuccessful. We show here that, by using large structural models and basis sets, both DeltaE(Q) and delta(Fe) values can be quite accurately predicted by using density functional theory. Four systems were investigated: the three 3-coordinate species [LFeX](0) (L = beta-diketiminate; X = Cl-, CH3-) and [Fe(SC6H2-2,4,6-tBu(3))(3)](-), in addition to an uncommon 2-coordinate high-spin ferrous thiolate, [Fe(SC6H3-2,6-mes(2))(2)] (mes = mesityl = 214,6-Me3C6H2)Both Gaussian-type-orbital and Slater-type-orbital basis sets were investigated, and both yielded DeltaE(Q) and delta(Fe) values in good accord with experiment. There were no improvements in these property predictions when (approximate) relativistic effects were included in the calculations. An MO analysis provided a detailed picture of the origin of the small DeltaE(Q) values seen in the 3-coordinate complexes. These results extend the scope of DFT/Mossbauer investigations beyond the 4-6-coordinate systems described previously to 2- and 3-coordinate systems, which should open the way to using these parameters in structure refinement, especially in large systems, such as proteins.