Inorganic Chemistry, Vol.34, No.8, 2054-2057, 1995
The Unsolvated Pentachloroferrate(III) Ion - X-Ray Crystal-Structure and Low-Temperature Magnetism of Tetramethylpiperazinium Pentachloroferrate(III)
Single-crystal X-ray diffraction study of the title compound, C8H20Cl5N2Fe, indicates crystallization in the monoclinic space group C2/c, Z = 4, with unit cell parameters a = 15.56(1) Angstrom, b = 8.876(3) Angstrom, c 12.487(6) Angstrom, and beta = 115.61(6)degrees, with a nearly ideal five-coordinate trigonal bipyramidal [FeCl5](2-) species in an ionic crystal lattice. A combination of Fe-57 Mossbauer spectroscopy and a.c. susceptometry confirms long-range magnetic order between 6 and 7 K with a 3-D antiferromagnetic ground state.