The preparation and characterization of the five-coordinate iron(II) porphyrinate derivative [Fe(TpivPP)(NO3)](-) (TpivPP = picket-fence porphyrin) is described. Structural and magnetic susceptibility data support a high-spin state (S = 2) assignment for this species. The anionic axial nitrate ligand is O-bound, through a single O atom, with an Fe-O bond length of 2.069(4) angstrom. The planar nitrate ligand bisects a N-p-Fe-N-p angle. The average Fe-N-p bond length is 2.070(16) angstrom. The Fe atom is located 0.49 angstrom out of the 24-atom mean porphyrin plane toward the nitrate ligand. From solid-state Mossbauer data, the isomer shift of 0.98 mm/s at 77 K is entirely consistent with high-spin iron(II). However the quadrupole splitting of 3.59 mm/s at 77 K is unusually high for iron(II), S = 2 systems but within the range of other five-coordinate high-spin ferrous complexes with a single anionic axial ligand. Crystal data for [K(222)]-[Fe(TpivPP)(NO3)]center dot C6H5Cl: a = 17.888 (5) angstrom, b = 21.500 (10) angstrom, c = 22.514 (11) angstrom, beta = 100.32 (3)degrees, monoclinic, space group P2(1)/n, V = 8519 angstrom(3) = Z = 4.